H.E.L.P. Missfire at cruising speed!!

[jayken302]

Ok, I really need some help on this one...
I got a 04 with 70k miles. It started just after I bought it, and very very slowly (like over the next 2,000 miles,) got worse. It has a very light miss while driving 35 to 55 mph and you can feel it in neutral or park while slight reving of the engine. About the same RPM to drive 35 to 55
mph. To describe it in detail it feels alot like a drive shaft out of balance.
I replaced all the coil packs, went with the Granatelli OEM replacement for 10% to 15% more spark. This did nothing, except for give me better response of the throttle.
I replaced the spark plugs twice first with NGK Plat, then with Autolites Plat.
I blocked the EGR with a plate to check if that was it.
Then I cleaned the MAS.
Lastly I found TSB 16941 which had me remove unplug the fuel pressure switch to check for a faulty fuel pump.
All did nothing and there are no fault codes.
A buddy of mine has a $2,000 Snapon scanner and we couldn't find anything wrong in there.
Oh yea, all the plugs are exactly the same looking showing a nearly perfect air/fuel mixture. Grey with a touch of black.
I ohmed out the injectors and they are all within .7 ohms of eachother.

Any thoughts??? I need all the help I can get!!!

[Pat]

Absent any codes coupled with a definite "feel" of the miss would suggest a sticky injector. The Ohm value of the injector doesn't reflect its dynamic operation.

Another possibility is a slow responding 02 sensor, prolly need to determine which bank.

Because the car hs 70K miles, items wearing out rear their ugly heads without throwing a code.

The throttle body has passages from the EGR valve input that may be clogged.

[Black_Noise]

try douching the PVC?

[MitchB]

Do a compression test.

Mitch

[Bobmiddle]

try the fuel filter.

[Glenn]

I would try and run 5 gallons of 101 through it and beat the p**s out of it. More MM's run rough and have engine issues that have not been beaten enough.

Glenn :burnout:

[BlownMerc]

If you have someone with a scan tool that can get into OBD Mode 6 data, there is a misfire history. Basically, it's a threshhold that the misfire percentage has to exceed to set a DTC, if it doesn't exceed that threshhold, no code, but the percentage is still present and viewable through mode 6. If you can pinpoint it to one cylinder, you might get a little closer to the problem. Also, the power balance function on the Ford scan tools can help, you can sit still, stall test it, drive it and watch for which cylinder is causing the concern. If it's random, and with all of the parts you've thrown at it, it may be RF interference. One bad coil has shut down a PCM on me before, the RF feedback to the PCM through the coil driver can wreek havoc. You may be out of driveway diag, time for one of us "dealership thieves" to take a look

[jayken302]

try the fuel filter.


Did that and nothing...
Thanks!

[jayken302]

try douching the PVC?

I replaced that today with no results...
Thanks!!

[jayken302]

Absent any codes coupled with a definite "feel" of the miss would suggest a sticky injector. The Ohm value of the injector doesn't reflect its dynamic operation.

Another possibility is a slow responding 02 sensor, prolly need to determine which bank.

Because the car hs 70K miles, items wearing out rear their ugly heads without throwing a code.

The throttle body has passages from the EGR valve input that may be clogged.

The O2 sensors bounce around alot, but they said that was normal.

I'll check the EGR passage tomorrow. (it is too cold tonight here in Chicago!!)

How should I check for a sticky injector? I took a long screwdriver to them this afternoon and they all sound the same with no miss clicks.

Thanks!!

[Pat]

Its not the clicks it's the spray. The PCM monitors the "clicks" the 02 sensors monitor the spray via the combustion process.

Admittedly this is a time consuming process, there are procedures for cleaning injectors while out of the engine.

I would look at the throttle body passages first, these passages are not visible without taking the TB apart.

The PCV cleaning was also a very good idea.

[justbob]

Off subject, but you are 10 minutes or less from me.

[jayken302]

Off subject, but you are 10 minutes or less from me.

Well I am actually in Carol Stream, which is about 20 minutes west off of North Ave.

[justbob]

I'm off county farm rd, one block north of the county buildings.

[jayken302]

Damn!
I am 1 mile north of North Ave just off of County Farm road!
If yours is Black, I have seen it many times up by the Jewel. I always hear it first, sounds like a bad ass mustang!!

[jayken302]

If you have someone with a scan tool that can get into OBD Mode 6 data, there is a misfire history. Basically, it's a threshhold that the misfire percentage has to exceed to set a DTC, if it doesn't exceed that threshhold, no code, but the percentage is still present and viewable through mode 6. If you can pinpoint it to one cylinder, you might get a little closer to the problem. Also, the power balance function on the Ford scan tools can help, you can sit still, stall test it, drive it and watch for which cylinder is causing the concern. If it's random, and with all of the parts you've thrown at it, it may be RF interference. One bad coil has shut down a PCM on me before, the RF feedback to the PCM through the coil driver can wreek havoc. You may be out of driveway diag, time for one of us "dealership thieves" to take a look

How much would this scan cost me at a Ford dealer?
Money is tight right now until Christmas is over.

[BlownMerc]

Most dealers (ours at least) charge one hour diag on driveability problems. If it gets to the point where additional diag or tests are required, like compression or mechanical engine diag like oil pressure and such, they will let you know of additional charges. Our dealer right now is at $70 for the first hour, some are as high as $100+ so ask up front. Let them know what you have done and let them produce the results. If you lead them in a certain direction with no results, they may try to lay some of the misdiagnosis on you, unfortunately it happens. Just take it somewhere you trust.

[jayken302]

Just an update...
I put one can of Sea Foam in the tank and about half a can in the intake.
So far after only 4 miles the miss "feels" less, which makes me feel like it is a clogged injector. If this doesn't work I am sending her to the Ford dealer for their Diagnostic service.

Anyone know which dealer is the best for that in the western suburbs of Chicago. I am basically 1 mile north of North Ave just East of West Chicago.

Thanks for all the help so far!!!

[justbob]

Fox valley Ford at 88 and orchard. Ask for Dave or Bill in the service dept. and tell him Bob from JK Services sent ya.:up:

Call first and make sure they still work there. Its been a year since i've been there.

[jayken302]

Damn!!!
The Seafoam didn't work for the miss, but holy S#@T that stuff rocks!!!
My intake is cleaner on the inside than the outside!!! The TB and plenum was really black and sooty before I used the seafoam, and now it looks bran new!!
Can I put this stuff in my Turbo Jetta? VW wanted to charge me $250 for an intake cleaning (which is probably just a $5 can of this stuff)

[Eric-Blk2004]

You can put it in anything

I am not sure if you tried this or not but mine was missing because the dealer washed the engine with a pressure washer and water got into the plugs. Mine were rusted, lucky I got it within a few days.

Yeah I am cool..

[jayken302]

Ok...
It was not the engine at all!!! I had Torque Converter Chatter. I dropped the pan, changed the filter, put 5.5 quarts of Mercron V, and a bottle of Ford Friction Midifier and 100 miles later then problem is almost gone. I can just barely feel it.
Its funny, I hate it when a non gearhead would want me to trouble shoot a problem from just their descriptions. So I am very sorry for explaining the problem incorrectly.
But happy as hell I got it!

[Pat]

Aha, so thats what torque converter chatter feels like. Heard about it but no one ever responded when it was fixed. Good show.

Just had my tranny fluid flushed and gushed, every 20K, and so far all is well.
The fluid price jumped a $1.25 since last time.

Regards,

[jayken302]

Well, it came back after 100 miles so I took it Atomic Transmissions in Villa Park, IL. They said it was defiantly the torque converter and want $650 to replace. Then they said that I might need a rebuild once they get it down and look inside. I have read alot of people replacing the torque conveters. Does anyone know if it safe to just replace the T/Q, or is their likely internal damage. When I dropped the pan, the magnet had about 1/8 of metal shavings all around it.
Oh yea. How hard is it to drop the trans in these cars. Easier or harder than a fox bodied mustang? That was the last one I did in my garage and it sucked!!!

[Marauderjack]

You will need KING KONG to get the cross member out!!!:eek::argue::mad2: That sucker is in there tight!!!:help:

Try another bottle of friction modifier...I have never seen it fail for TC shudder but sometimes it takes two bottles and about 300 miles of driving....ya got nothing to lose at this point...except the shudder!!:beer:

Good Luck!!

Marauderjack:burnout: