I own a 2003 GT with an automatic transmission and I am having a lurching or bucking issue. When a keep the car at a steady speed of 30-38 miles per hour it feels like a have an intermittent skip. I have have the car checked several times by a local shop and also by Ford and I don't have a skip condition. I even had all the coils replaced with MSD coils. I have also replaced a sensor that goes to the Cat and tested the throttle position sensor. A few have told me that maybe the transmission is hunting but if it was it would be more pronouced and I would see a rise or drop in the RPM's. To me it feels like the torque converter is locking and unlocking. I even have turned the overdrive off and on when it starts doing it to see if it's RPM related versus a speed related issue but there is no change in the lurching feeling. It is driving me crazy. I bought the car used and I now think that maybe that is why is was traded in. If I drive slower than 30 or faster than 45 it never does it. The engine seems to run great and the transmission shifts fine, at the proper speeds and down and up shifts fine. It's just at the 30-38 or 40 miles per hour that something starts acting up. I also have have the car scoped twice and there are no codes. I don't want to spend big bucks on a replacement converter if there is nothing wrong with it. The bucking, lurching or skip feel has been with the car since I bought it (about 6 months). Any ideas?

 

Mine did the same thing at slower speeds. It's just the lock up on the converter at low speeds and RPM's. Put in a 4.10 gear and my problem prety much went away.

 

Does the car have a chip or aftermarket tune in it. If so it could be all in the settings of such. Like I said in another tranny post I had some wierd problems when I was playing around with tranny settings in my Sniper software, I was just trying to learn what different setting did to the car. All my problems went away when I just stuck to the basics, shift firmness and preasure settings.

 

I have changed the gears to 3:73 with no change in the condition. I also have a SCT tuner but the car had the problem before the turner and still has it with the tuner. For the winter I have the transmission set to stock but over the summer I had it set for performance with higher shift points and firmer shifts. Regardless of how I have it set or with the stock gear set nothing has change the lurching condition. Is the torque lockup adjustable? What else could it be?

 

Yes it is in Sniper software not sure about SCT. I also think that throttle position comes into play with it some how too! One thing you might try if you can, In Sniper software I can turn off all torque reducing calculations, if you can do that in the SCT it might be a way to trouble shoot some more.