AOD problem??

[mystang02gt]

I have an 02 Gt convt. have a couple mods pulleys, cold air, x-pipe, tune and mufflers. My problem is that when i drive at about 35mph with little throttle the car kinda jerks. It seems to only happen when the car is in 3rd at 35. Any ideas???? The car only has 50,000 miles on it.

 

[04YELLOWGT]

It could be a misfire. I would replace the plugs and see if it still does it. My car was doing it in OD at around 60, I swaped out my plugs and she runs perfect now.

 

[mystang02gt]

I don't think its the plugs i just did them last month this problem just started. Im hoping it just needs a trans flush.

 

[Mike97gt]

I don't think its the plugs i just did them last month this problem just started. Im hoping it just needs a trans flush.

I doubt it's a trans problem, that is the exact speed and gear a misfire is most noticable.. most likely a coil went bad, or if you used non motorcraft plugs that can be the cause too..

I have removed many plugs less than a month old that were not motorcrafts for misfires over the years.. In fact the last time I saw this was a month ago, it was a v6 mustang the guy put NGK plugs in a few weeks earlier and it developed a bad misfire.. replaced with motorcraft stock plugs and ran perfect.

transmission shudders are RARE, be carefull this is the way some trans shops and dishonest techs like to rape people and sell them trans repairs that are not needed. I have known a few trans rebuilders sell a "trans rebuild" and then not touch the trans and fix the spark plug and or coil out of their own pocket so they can steal 15-18 hours labor..

I knew one scum bag I used to work with that kept good used coils and plugs for this exact reason.

 

[nyuk98gt]

Gents:

I will put my money on the torque converter locking/unlocking at that speed. If you lightly touch your brakes (just enough for the brake lights to come on/activate the brake on/off switch) and the problem stops it's because the torque converter is unlocked (with brakes applied). The locking schedule can be adjusted in the tune.

Chris

 

[04YELLOWGT]

Gents:

I will put my money on the torque converter locking/unlocking at that speed. If you lightly touch your brakes (just enough for the brake lights to come on/activate the brake on/off switch) and the problem stops it's because the torque converter is unlocked (with brakes applied). The locking schedule can be adjusted in the tune.

Chris

Well mine was actually bad plugs but his it could be but I wouldn't think so with an stock auto and stall.

 

[mystang02gt]

well im going to do the trans service to it and see what happens. I have the diablo tuner so the only things ive messed arround with is advancing my timing a degree and got rid of my govener so far.

 

[Mike97gt]

well im going to do the trans service to it and see what happens. I have the diablo tuner so the only things ive messed arround with is advancing my timing a degree and got rid of my govener so far.

Keep us updated..

Well mine was actually bad plugs but his it could be but I wouldn't think so with an stock auto and stall.

most likey his problem is a secondary ignition problem.. extremely common problem on the 4.6 they develop a slight miss that is most noticable with the converter locked in 4th gear.. if you go up a hill with the converter locked you will get it to shudder even more.

most of the time is not enough of a misfire for the misfore monitor to pick up and set a p030x code, and if KAM was cleared and or the battery disconnected recently the misfire monitor might not be active anyways.

If he had access to a IDS he could watch power balance and set a recording starting at 30mph and drive up a incline at low rpm's and then tip in the gas lightly and he would be able to see what cylinder was dropping out if it is a misfire

If nothing dropped out when he felt the shudder then you would start looking at driveline but consider this..

In ten years of working on fords I have seen this complaint hundreds of times and all of them was a ignition failure ( plug, wire on 98 and earlier, coil or coil packs)

 

[mystang02gt]

Trans service is done and car runs great!!!! I found out that the old cougars and towncars had the same problem.

 

[BobHyatt]

one other odd thing is it could be the A/C cycling switch. If it goes nuts, it will rapidly cycle the A/C clutch, which will make the motor jerk significantly and feel just like a miss or tranny problem. If the problem doesn't happen with the A/C off, that could be your issue. If it happens with the A/C off, then this isn't the issue...

 

[Mike97gt]

one other odd thing is it could be the A/C cycling switch. If it goes nuts, it will rapidly cycle the A/C clutch, which will make the motor jerk significantly and feel just like a miss or tranny problem. If the problem doesn't happen with the A/C off, that could be your issue. If it happens with the A/C off, then this isn't the issue...

yeah that can cause a feeling like a miss.. the late 90's taurus use to get a idle surge from this.

Trans service is done and car runs great!!!! I found out that the old cougars and towncars had the same problem.

Thats good.. I am surprised that it was a converter shudder.. Hopefully you will get lucky, my bosses son had a 98 explorer that had a shudder and we flushed it and it was ok not perfect but a lot better untill he totaled the thing a year later..

the old T-bird/ cougar and mark VIII had converter issues back in the day but it's still somewhat rare..

 

[CobraRed_96_GT]

That's exactly how my TC shudder felt, at the same speed with light throttle. Make sure you're using Mercon V now as well.