Transmission Or Engine

[maxxedout]

Got a 99 GT automatic, when the transmission goes into over drive the car jerks like its not locking up. Today took it to trans shop and he hooked up the computer and drove the car and he thinks the engine is misfiring and causing the jerking. Would this not set a code for misfire and could I take it to the dealer and have them check for a misfire. Also would anything else cause this, motor runs great and idles fine. Plugs have been changed and one coil pack.

 

[90sickfox]

Misfires can cause that issue. You'd have to hook it up to a good scanner (solus...autel) and watch the misfire counter. Sometimes you can have a miss that doesn't trip the CEL.

 

[maxxedout]

Thanks sickfox, taking it to the dealer Tuesday and they said they could do it . Gonna cost 90 bucks but if they can find it ,will be worth it..Thanks.

 

[Special20]

I have a 2003 Convertible GT and this also happens to me but it seems it only happens when I hit 45 mph and stay there. As I am accelerating past 45mph, it shifts perfect. What I have read, a transmission service and a transmission cooler almost always solves this problem.

 

[maxxedout]

Ok got to the dealer today and they found misfires on 2,3 and 4. Went to autozone got three coil packs and replaced, I cant tell the difference in the way it runs still has the jerking feel in OD. What else would cause tis??? I also put in new plugs all Motorcraft.

 

[BrothersPerformance]

I would imagine that if they found 3 coil packs failing, then there may be issues with the remaining coil packs. Did you make sure the spark plugs were gaped correctly? Were there any codes relating to the transmission at all? When was the last time the transmission was serviced?

 

[maxxedout]

All plugs were changed last month and gapped, No codes on transmission, trans guys are the ones that sent me to dealer to check for misfire. Trans was serviced when I bought the car 13 months ago. Hope this helps, having a buddy of mine reread the misfires. Wondering if dealer gave me the wrong cyls because I would not let them fix it for 445.00. Just wondering ??

 

[maxxedout]

Ok had it checked again no misfires found but still has the vibration between 45 and 55. Had another guy drive it and he thinks it feels like a drive train vibration. Going to check pinion bearings and u joints and trans tail shaft. Running me nuts!!!!

 

[BrothersPerformance]

Are you still having the original issue with surging or is now just a vibration?

 

[maxxedout]

seems to be only the vibration now.

 

[maxxedout]

Well have changed all coil packs and still has the surge jerky feeling around 1500 rpm when in top gear. What else would cause a misfire at high rpm??? To me feels more like the torque converter but trans shop says not in trans , what should I do next??

 

[Pantera2013]

ya, id change all the coil packs cuz the other ones are soon to fail on the car. id take it too the dealership and explain the problem its having and see if they know what it is.