low idle buck

[03blackmerc]

this question is actually for my brothers MM. at low idol like the lowest end of overdrive or any gear hes getting a constant buck. When he acclerates no misfire, but when he stomps on it youll get a couple of little misfires throughout the RPM range. he already replaced plugs, fuel filter, and ran injector cleaner through it. he once thought it was a tranny problem, but he only has 85,000. i have 120,000 and never have had anything happen like this. anythoughts?

[SpartaPerformance]

Misfires through the rpm range?? Do you mean detonation? If that's the case then you may have some bad gas, sounds like you replaced everything as far as tune up goes but I'm just guessing here based on your description.

[03blackmerc]

we also thought maybe a bad tank of gas, but this has been going on for about a month now. i was thinking maybe an idle are control problem? i had a similar buck on my crown vic, but it also had a surge at idle. how often do you think O2's should be changed if it dosnt throw a code?

[4play]

bad coil? best bet woud be to take it to ford and get them to scope it out, or, take a risk and buy a new coil and swap one out at a time till you find the one that is missing.

[Marauderjack]

Mine did that several years ago and the Granatelli solid connectors between the coils and plugs fixed it right up.....never missed a lick since!!!:beer::bows:

[YOCKIT]

Had a 99 intercepter, trans shutterd, it feels like a misfire. Does it misfire out of gear?

[Marauderjack]

If you suspect it is indeed trans/TC shudder PM me and I'll give you a fix that works 100% of the time and is less than $10.00!!:beer:

I'd post it here but my flame suit is at the cleaners!!!;) :rolleyes:

[W4LTD]

Oh, Two Sense Her

$0.02 'er

Owwww, Too Censor'd

[fastf50rd]

Its not throwing a check engine light at all, or doing it out of gear.

[03blackmerc]

not throwing a light at all. only in gear at low RPM the worste. it seems more like a misfire to me. so maybe try new coils first?

[Marauderjack]

not throwing a light at all. only in gear at low RPM the worste. it seems more like a misfire to me. so maybe try new coils first?

See post #5 above!!:beer:

[fastf50rd]

Mine did that several years ago and the Granatelli solid connectors between the coils and plugs fixed it right up.....never missed a lick since!!!

Im gonna try this next. After I did the plugs, I wanted to get these anyway. Where's the best place to order them? thanks for the replies.

[03blackmerc]

hmmmmmmmm maybe i'll try the 02 sensors ha ha. ive never changed mine, when do u usually change the 02's?

[Marauderjack]

hmmmmmmmm maybe i'll try the 02 sensors ha ha. ive never changed mine, when do u usually change the 02's?

O2 sensors last a long time...........mine are are going on 7 years old and 212K miles with 128K of those miles being supercharged....still working fine!!!:beer:

[babbage]

O2 sensors last a long time...........mine are are going on 7 years old and 212K miles with 128K of those miles being supercharged....still working fine!!!:beer:

I'd say close to 100K is a good time to change the O2's
Clean the MAF too is a good idea.

however my money is on ignition - bad COP or connector, boot cracked etc.

[Black_Kannin]

Mines does the same thing....(inputting knowledge)....Ima get a few things done to take care of that.

[fastf50rd]

I've also noticed it bucks/hesitates alot less if not at all when the car is cold. Idk if this would narrow anything down.

[fastf50rd]

Alright, now its getting really annoying. I just put in a new set of granatelli cop wires to no affect. Still hesitates in the exact same way. Only at low low rpm's under slight acceleration. Just bucks like mad. Please help.

[Kennyrauder]

No engine problems ...amazing. My Marauder is a mere child for an 03... 42k miles & supercharged for the last 25K miles. Guess I'm OK for awhile. Take care.

[Marauderjack]

Only other thing I can think of is EGR valve......mine was surging at low speeds so I replaced it and that seemed to fix it.....

Later on it had the same surging but now with the blower so my tuner turned the EGR function down to 60% at max vacuum...seemed to fix it and the EGR still functions!! :beer:

[YOCKIT]

If thier is a misfire, thier should be a engine light. This sounds like trans shutter.

[fastf50rd]

[QUOTE][/If thier is a misfire, thier should be a engine light. This sounds like trans shutter.QUOTE]

This is what i'm starting to fear. I've been told to try a few oz's of friction modifyer. I couldn't find that so I tried some lucas oil which contains friction modifiers. It didn't seem to help. Anything else I could try?

[YOCKIT]

I haven't heard of anything that will fix it. Outside of rebuild. Just keep driven. It can be driveable for a long time.

[RF Overlord]

2 things. First, if it's torque converter shudder, then it will only happen when the TC tries to lock up. If you can get it to happen for more than a few seconds, try holding the accelerator steady while it's happening and tap the brake pedal. If it stops doing it instantly, then it's TC shudder.

Second, if it IS TC shudder, Lucas Oil is worthless for this purpose. Your need to either add Ford XL-3 friction modifier or LubeGard's Dr. Tranny, or change the transmission fluid entirely. Either way, it can take as much as a couple of hundred miles of driving for the problem to go away completely.

You mentioned 85,000 miles...has the ATF ever been changed? If not, nevermind the additives, just get it flushed with fresh Mercon V.

[Marauderjack]

2 things. First, if it's torque converter shudder, then it will only happen when the TC tries to lock up. If you can get it to happen for more than a few seconds, try holding the accelerator steady while it's happening and tap the brake pedal. If it stops doing it instantly, then it's TC shudder.

Second, if it IS TC shudder, Lucas Oil is worthless for this purpose. Your need to either add Ford XL-3 friction modifier or LubeGard's Dr. Tranny, or change the transmission fluid entirely. Either way, it can take as much as a couple of hundred miles of driving for the problem to go away completely.

You mentioned 85,000 miles...has the ATF ever been changed? If not, nevermind the additives, just get it flushed with fresh Mercon V.


^^^+10^^^:beer:

[fastf50rd]

Well, tried doin the brake thing as mentioned above to see if its TC shudder. Still bucks while hitting the brake. Took it to ford for a tranny flush n fluid change. They charged me 90 bucks to tell me they think it could be the 1 and 6 coil being weak, but they wouldn't know 4 sure unless they did a stress test which was another 90. So I said F that i've been ripped off enuff. Gonna change 1 and 6 and see if it works. What's the firing order? Which is 1 and 6 coil? thanks.

[fastf50rd]

I just replaced those two coils and all is well. Runs mint again. Almost 4got what the was like. I had to go with Borg Warner, all that was avail on short notice. These any good? Also, how did the techs at ford know what two coils were causing trouble without a check engine light being on?

[bones]

I have an 2003 that was bucking & or misfiring.

Check all the connectors at the coils where the wiring plugs in to the coil.

Make sure the connectors are seating properly & pay close attention to the wire terminals on the connectors. Make sure they are not pushing out of the harness.
I had a broken plastic clip internally at the connector. Causing the terminal to push out of the connector & make the car misfire under acceleration.
I found the problem while installing a new set of coils I ordered for the car. If you are going to replace the coils. I suggest replacing all of them with WEAPON X COILS. You will feel a difference.
Good Luck!

[fastf50rd]

Did you not read the above post. lol. thanks tho.