Tracking down a Misfire

[Blk04MM]

A slight misfire, stumble or puttering. I'm going to call it a misfire because when you give it throttle from a stop it stumbles a bit then goes. You can hear it in the exhaust. Basically anytime the car is under a little bit of a load it stumbles. Very very light throttle its not there. When I put the car in neutral and give it gas it stumbles in the low rpm but when it's high it's no problem.

It started yesterday so the plugs were changed. After changing them the misfire was more noticeable. I used FMC platinum.

Couldn't figure it out so I pulled the driver side valve cover off and replaced the gasket and the spark plug tube seals due to a slight drop of oil in valley #5. The seal cleared that oil right up and I changed the #5 COP just incase oil caused it to go. But misfire still there

I started the car and pulled every COP one by one and the car noticeably changed tone so everything is firing. Plus I HAVE NO CEL light

I Pulled off the EGR sprayed it down with carb cleaner, put it back on and still have the misfire.

You can hear it in the exhaust. Basically anytime the car is under a little bit of a load it stumbles. Very very light throttle its not there. When I put the car in neutral and give it gas it stumbles in the low rpm but when it's high it's no problem.

IM LOST NOW.

Wats next? Check Injectors? New EGR? Check fuel pump(there has been a very faint howl since I got the car)

[CWright]

PM sent......

[Blk04MM]

PM sent......

Replied......

[Blk04MM]

For possible voltage issues. I just sat in the car and looked at the gauge(stock). Cranking up its 10 volts. When it starts its dead on 12 then slowly rises to 14.

Just stopped by orileys they did a battery check. Car on it was 12.5
I forgot what the Car off was but he said they both are good.

[gdmjoe]

.
clean the MAF sensor.
check the throat / plate of the throttle body for carbon.
what's the voltage of the TPS?

[Blk04MM]

.
clean the MAF sensor.
check the throat / plate of the throttle body for carbon.
what's the voltage of the TPS?

Trying to locate the tool to clean the MAF

I will spray some carb cleaner through the TB but I doubt it fixes it.

No volt checker for the TPS

[B.C. Bake]

For possible voltage issues. I just sat in the car and looked at the gauge(stock). Cranking up its 10 volts. When it starts its dead on 12 then slowly rises to 14.

Just stopped by orileys they did a battery check. Car on it was 12.5
I forgot what the Car off was but he said they both are good.

Car running the volts at the battery usually are around 14.2V or something close to that.:confused:

[Blk04MM]

Car running the volts at the battery usually are around 14.2V or something close to that.:confused:

I actually don't know. Hopefully someone can chime in.


With AC, radio and lights on the volts on the factory gauge drops to 11ish 12. If I hit the window button it's damn near at 10 if not on 10

When I hit the gas it goes back up to 13-14

[B.C. Bake]

I actually don't know. Hopefully someone can chime in.


With AC, radio and lights on the volts on the factory gauge drops to 11ish 12. If I hit the window button it's damn near at 10 if not on 10

When I hit the gas it goes back up to 13-14

If you could get a voltmeter it would give a more accurate reading across the battery terminals, and with it running should be a strong 13-14 volts.:)

[Blk04MM]

If you could get a voltmeter it would give a more accurate reading across the battery terminals, and with it running should be a strong 13-14 volts.:)

Anything lower would cause a misfire under load? :confused:

[1stMerc]

You got a bad coil or two. Not noticeable at idle, but shows up at mid throttle or when you speed up from 35-40 mph and clears up around 50 and above.

[Blk04MM]

You got a bad coil or two. Not noticeable at idle, but shows up at mid throttle or when you speed up from 35-40 mph and clears up around 50 and above.

So the old "pull each coil one by one" with the car on to see if the tone changes or not was :bs: ?

One COP is brand new (#5)


If so I have a extra COP I bought and was going to return but I guess I can use it to start swapping around to see if anything gets better.

Car can be in park and I give it a good romp you can tell its missing as well.
Basically anything involving the car being under load its missing, rolling, from a stop and in park

[Blk04MM]

Another issue***
Car was idling high and holding rom after a rev. I checked the motor and heard a whistle. Looked at the back of the intake and the pcv hose was damn near sucked shut. I got it pulled off its like burnt/melted smh.

Any good replacements or "mod" to do now? Seems as if the plastic tube is a bit short for that setup

[1stMerc]

So the old "pull each coil one by one" with the car on to see if the tone changes or not was :bs: ?

One COP is brand new (#5)


If so I have a extra COP I bought and was going to return but I guess I can use it to start swapping around to see if anything gets better.

Car can be in park and I give it a good romp you can tell its missing as well.
Basically anything involving the car being under load its missing, rolling, from a stop and in park

That was the way I did it. It is time consuming, but been going stong for the past 50k.

Or you can just replace them all. There is numerous threads on the subject.

[Blk04MM]

That was the way I did it. It is time consuming, but been going stong for the past 50k.

Or you can just replace them all. There is numerous threads on the subject.

I'm not asking for a "how to" I'm asking for help as to what else could it be before throwing money at injectors or a $400 set of COPs

I have another NEW COP I can move around and see if anything changes but as for not I'm stuck. The PCV rubber connector on the intake side decided to fail so I can't check COPs without it. Nothing open that carries hoses this late. :shake:

[Krytin]

At lot less than $400 for a set of oem FoMoCo COPs from Sparta. I just did mine last month because I had the exact same problem as you. Had 132K miles on the original COPs.

[1stMerc]

I'm not asking for a "how to" I'm asking for help as to what else could it be before throwing money at injectors or a $400 set of COPs

I have another NEW COP I can move around and see if anything changes but as for not I'm stuck. The PCV rubber connector on the intake side decided to fail so I can't check COPs without it. Nothing open that carries hoses this late. :shake:

Not a "how to" just what worked for me when I had your issue.

You talking about the rubber section on the intake that the plastic tube goes into, correct? By failed, what do you mean?

[Blk04MM]

At lot less than $400 for a set of oem FoMoCo COPs from Sparta. I just did mine last month because I had the exact same problem as you. Had 132K miles on the original COPs.

Right now I can get some from the local parts store to see if it cures it. I bought two to move around and see


Not a "how to" just what worked for me when I had your issue.

You talking about the rubber section on the intake that the plastic tube goes into, correct? By failed, what do you mean?

Got cha.
And it failed because it got a hole sucked thru it. Somehow the space between the plastic pipe and the rubber boot was sucked shut and a hole quickly appeared.

[Krytin]

A lot of the coil failures are intermittent ones - they don't misfire all of the time. The swap one out method may not work too well. Plus figure all of the coils have the same cycles/hours on them, if one is bad how much longer will the rest last?
If you changed the plugs and it got worse or not any better AND your sure there is no bad connectors to the coils, there appears to be a lot of people changing coil sets @ +120k miles.
It is a lot of $$ to roll the dice with but if you have eliminated all other possibilities...........

[Blk04MM]

A lot of the coil failures are intermittent ones - they don't misfire all of the time. The swap one out method may not work too well. Plus figure all of the coils have the same cycles/hours on them, if one is bad how much longer will the rest last?
If you changed the plugs and it got worse or not any better AND your sure there is no bad connectors to the coils, there appears to be a lot of people changing coil sets @ +120k miles.
It is a lot of $$ to roll the dice with but if you have eliminated all other possibilities...........

Yeah i thought about that last night so I went ahead and changed out ALL of the boots and springs ...the problem is still there

[Blk04MM]

Any way to test the coil connectors? Or I'd have to but an 8 set and swap em all out?

[Blk04MM]

I havent changed the PCV.

Could that cause a misfire or stumble under load?

[RF Overlord]

It could, but it's way down there on the list. If it isn't ignition-related, I'd lean more toward EGR/DPFE.

[Blk04MM]

It could, but it's way down there on the list. If it isn't ignition-related, I'd lean more toward EGR/DPFE.

I removed the EGR and sprayed a good amount of cleaner in it. All of the cleaner came out clean.

[Blk04MM]

Plus the car cranks and idles just fine that's why I ruled out the EGR

[RF Overlord]

Just because it's clean doesn't automatically mean it functions correctly. I believe there's a procedure whereby you put one of those hand vacuum pumps tools on it and pull a vacuum while the motor's idling and see if it stumbles...I don't have the exact procedure handy.

[Blk04MM]

Just because it's clean doesn't automatically mean it functions correctly. I believe there's a procedure whereby you put one of those hand vacuum pumps tools on it and pull a vacuum while the motor's idling and see if it stumbles...I don't have the exact procedure handy.

So even if it starts and idles fine a bad/failing EGR can still cause misfire/stumble under load while driving/pull off from a stop and even in neutral? :confused:

[Blk04MM]

With the AC on in park and giving it gas it's more noticeable

[Krytin]

The DPFE will cause a rough running engine but not a miss that you can actually hear in the exhaust - I had a bad DPFE on my '04 CV. The DPFE is not the actual EGR valve but a differential pressure switch that monitors flow for the EGR valve.

Testing the connectors would involve continuity testing at the plug and doing a wiggle test while the meter is connected to the pins. I just don't know how to connect a meter to create the "loop" for the continuity.

[Blk04MM]

The DPFE will cause a rough running engine but not a miss that you can actually hear in the exhaust - I had a bad DPFE on my '04 CV. The DPFE is not the actual EGR valve but a differential pressure switch that monitors flow for the EGR valve.

Testing the connectors would involve continuity testing at the plug and doing a wiggle test while the meter is connected to the pins. I just don't know how to connect a meter to create the "loop" for the continuity.

Definitely hear it in the exhaust while driving. I've heard the fuel pump howling very faintly at times. Could it be bad?

[Krytin]

Could be on it's way - I don't recall, you're not running any booster pump or aftermarket pump are you? The OEM pumps rarely make any noise you can hear except for the key on run up to pressure before you actually crank it.

[Blk04MM]

Could be on it's way - I don't recall, you're not running any booster pump or aftermarket pump are you? The OEM pumps rarely make any noise you can hear except for the key on run up to pressure before you actually crank it.

Nope. Bone stock pump. I hear it engage when I turn the key on. When it cranks and I'm sittin there listening I can hear a faint howl. It's been like that for a while off and on though. 98% I use shell gas so I know it's not a cheap gas situation.

[Krytin]

Nope. Bone stock pump. I hear it engage when I turn the key on. When it cranks and I'm sittin there listening I can hear a faint howl. It's been like that for a while off and on though. 98% I use shell gas so I know it's not a cheap gas situation.

They do just wear out. From what I've been able to understand so far, the worst thing for the pump is to run on a low tank all of the time. Brand of gas should have little to no effect on the pump. They run in the tank submersed and when you start to hit 1/4 tank and lower it doesn't have as much fuel to cool it - heat shortens the life of just about everything.

[Blk04MM]

They do just wear out. From what I've been able to understand so far, the worst thing for the pump is to run on a low tank all of the time. Brand of gas should have little to no effect on the pump. They run in the tank submersed and when you start to hit 1/4 tank and lower it doesn't have as much fuel to cool it - heat shortens the life of just about everything.

I've read many members run their fuel low and some do it often. I usually ride till the light comes on. I've never been a fan of keeping it above half or etc.... Yeah its cheaper but Why not burn off the new fuel vs having it sitting and putting new fuel on top. That's just me though. Maybe it did cause it to go bad. I don't know. I'm driving it to the shop later to have them look at it. Check fuel pressure and etc... Hopefully this is resolved tonight.

[Blk04MM]

I do notice I'm now at a solid 14 volts after replacing all coils&boots

[tbone]

I've been extremely happy with my Accel Super Coils. Ebay has 'em for $156/set of 8.

http://www.ebay.com/itm/Accel-140034-8-Super-Coil-Ignition-Coil-Set-/400539193357?pt=Motors_Car_Tru ck_Parts_Accessories&fits=Year%3A2003%7CMake%3AMerc ury%7CModel%3AMarauder&hash=item5d41ff100d&vxp=mtr

[Blk04MM]

Hooked up the solus ultra and getting misfire mainly on cyl 2&3 under load

Battery volts drop to 11 when under heavy load.


Changed the TPS

The new plugs are the Motocraft sp433 iradium that I read on here to get.

STILL misfiring

[gdmjoe]

Blk04MM - Trying to locate the tool to clean the MAF
http://www.bavauto.com/assets/product_images/0/05110.jpg
.

[Richy04]

Just so you know, some tunes will not tell you a coil is bad no matter how much it misfires. You won't get a flashing check engine light (indicative of a misfire stored in pending or triggered code list) If you roll back to your stock tune, you have a better chance of finding the misfire because the Ford tune may lock in on which one is the problem. All of the diagnostic mumbo jumbo is stripped from some of the tunes making it impossible in some cases to see a problem. The stock tune will pay more attention to whats going on since the PID's are stored in it and the rear O2's are on which will tell the ECU that the level of raw fuel is elevated. Without the rear O2's on the engine will not see the bit of raw fuel squeaking by the cylinder that is misfiring.

[SC Cheesehead]

They do just wear out. From what I've been able to understand so far, the worst thing for the pump is to run on a low tank all of the time. Brand of gas should have little to no effect on the pump. They run in the tank submersed and when you start to hit 1/4 tank and lower it doesn't have as much fuel to cool it - heat shortens the life of just about everything.

^^^^^^ Yup, have been told the same thing by several different folks, all of them Ford mechanics/engineers.


I've read many members run their fuel low and some do it often. I usually ride till the light comes on. I've never been a fan of keeping it above half or etc.... Yeah its cheaper but Why not burn off the new fuel vs having it sitting and putting new fuel on top. That's just me though. Maybe it did cause it to go bad. I don't know. I'm driving it to the shop later to have them look at it. Check fuel pressure and etc... Hopefully this is resolved tonight.

Won't happen, new fuel and old fuel don't segregate, they'll mix in the tank.

[Blk04MM]

All coils aren't the same :confused: I keep hearing that two cylinders require a different coil.








http://www.bavauto.com/assets/product_images/0/05110.jpg
.

I know that. I was trying to locate the tool to remove the MAF from the housing


I've been extremely happy with my Accel Super Coils. Ebay has 'em for $156/set of 8.

http://www.ebay.com/itm/Accel-140034-8-Super-Coil-Ignition-Coil-Set-/400539193357?pt=Motors_Car_Tru ck_Parts_Accessories&fits=Year%3A2003%7CMake%3AMerc ury%7CModel%3AMarauder&hash=item5d41ff100d&vxp=mtr

Might order a set of those just for spares thanks


Just so you know, some tunes will not tell you a coil is bad no matter how much it misfires. You won't get a flashing check engine light (indicative of a misfire stored in pending or triggered code list) If you roll back to your stock tune, you have a better chance of finding the misfire because the Ford tune may lock in on which one is the problem. All of the diagnostic mumbo jumbo is stripped from some of the tunes making it impossible in some cases to see a problem. The stock tune will pay more attention to whats going on since the PID's are stored in it and the rear O2's are on which will tell the ECU that the level of raw fuel is elevated. Without the rear O2's on the engine will not see the bit of raw fuel squeaking by the cylinder that is misfiring.

Never thought of that. Thanks. But my cats are neutered... All of them so I'm sure the stock tune would throw those all day but I will revert to stock later to see. Thanks


^^^^^^ Yup, have been told the same thing by several different folks, all of them Ford mechanics/engineers.



Won't happen, new fuel and old fuel don't segregate, they'll mix in the tank.


Ok. I'll change out my FP soon I'm sure it's still the OEM along with the fuel filter

[Blk04MM]

Bought all new coil packs. Sprayed the MAF and new fuel filter.

Car is back to normal. Thanks for all the input from everyone

[CWright]

Bought all new coil packs. Sprayed the MAF and new fuel filter.

Car is back to normal. Thanks for all the input from everyone

Glad you got it figured out. Now you can come on up to Marauderville! :D

[Blk04MM]

Glad you got it figured out. Now you can come on up to Marauderville! :D

Thanks man. I might. Not 100% sure yet.

[SC Cheesehead]

Bought all new coil packs. Sprayed the MAF and new fuel filter.

Car is back to normal. Thanks for all the input from everyone


Good stuff! Glad you got the issues resolved.


Glad you got it figured out. Now you can come on up to Marauderville! :D

^^^^^ What he said, would be great if you could make it.

[sflrainmaker01]

Bought all new coil packs. Sprayed the MAF and new fuel filter.

Car is back to normal. Thanks for all the input from everyone


Glad to hear you got it worked out!! :beer:

[Blk04MM]

Good stuff! Glad you got the issues resolved.



^^^^^ What he said, would be great if you could make it.

I'm gona try. Now I have a knocking dashboard and my volts are dropping to 10-11 under WOT. don't know if its batt, atl or voltage regulator :shake:

[Blk04MM]

Good stuff! Glad you got the issues resolved.



^^^^^ What he said, would be great if you could make it.


Glad to hear you got it worked out!! :beer:

Thanks man. I'm almost 100%

[Krytin]

I'm gona try. Now I have a knocking dashboard and my volts are dropping to 10-11 under WOT. don't know if its batt, atl or voltage regulator :shake:
The program turns the alternator field voltage off @ WOT effectively shutting it off - should come on again shortly after getting off the go pedal. It's the normal factory setup.

[Blk04MM]

The program turns the alternator field voltage off @ WOT effectively shutting it off - should come on again shortly after getting off the go pedal. It's the normal factory setup.

It definitely goes right back up once the pedal is released. Thanks.

[sflrainmaker01]

I'm gona try. Now I have a knocking dashboard and my volts are dropping to 10-11 under WOT. don't know if its batt, atl or voltage regulator :shake:

FWIW, based on some of your first posts, it doesn't sound like that alternator is doing its job. At one point, I recall you saying it was checked out and the output was 12.5v. That's low IMO. It should be 13.6v to 14.2v with the engine running at idle, unless you have some under-drive pullies. I know there are little diodes in the alternator that can do some crazy stuff.:rolleyes:

[Blk04MM]

FWIW, based on some of your first posts, it doesn't sound like that alternator is doing its job. At one point, I recall you saying it was checked out and the output was 12.5v. That's low IMO. It should be 13.6v to 14.2v with the engine running at idle, unless you have some under-drive pullies. I know there are little diodes in the alternator that can do some crazy stuff.:rolleyes:

Yeah it definitely wasn't those numbers at idle. I may just change it to have a fresh one since I'm up in miles anyway. Just trying to get the voltage regulator checked

[gdmjoe]

Blk04MM ... I know that. I was trying to locate the tool to remove the MAF from the housing
Welp if you know that, then you know that you don't have to remove the sensor to clean it.

Disconnect the intake tube from the housing, the MAF and airbox top from the airbox, and spray the sensor thru the housing.

Here's the tool ...
http://www.testequipmentdepot.com/xcelite/images/s3163.jpg

[Blk04MM]

Welp if you know that, then you know that you don't have to remove the sensor to clean it.

Disconnect the intake tube from the housing, the MAF and airbox top from the airbox, and spray the sensor thru the housing.

Here's the tool ...
http://www.testequipmentdepot.com/xcelite/images/s3163.jpg

Been got it done. I wanted to remove it to inspect it and clean.

[cat in the hat]

Welp if you know that, then you know that you don't have to remove the sensor to clean it.

Disconnect the intake tube from the housing, the MAF and airbox top from the airbox, and spray the sensor thru the housing.

Here's the tool ...

http://www.testequipmentdepot.com/xcelite/images/s3163.jpg


I have a question about this but I don't want to derail this thread, so I'm going to start a separate one here :

http://www.mercurymarauder.net/forums/showthread.php?p=1321357#post1 321357