My car feels jerky (technical term). When I am cruising at a constant speed on level ground the gas feels like it's either OFF or ON. The slightest change of the gas pedal and I feel the car jerk slightly. It's just not smooth. I recently put a new FPD and FPR on. I guess it could also be the something related to removing the UIM during the process. I'm going to try adjusting the throttle cable this weekend, but I doubt that's the problem. ISC? TPS?

 

When you are on a gentle cruise, your car is most likely in closed loop mode. The computer references the O2 sensor and attempts to lean out the mixture for economy. If you have the stock computer, it might be time for a new O2 sensor. If you have a PFC, this is a very common occurrence.. the PFC doesn't seem to handle closed loop as elegantly as the factory computer. Most PFC users have Disabled O2 Feedback to correct this. It can be done from the commander. You don't need a datalogit.

..dave

 

I have a stock computer. The O2 sensor only has 4000 miles on it, but that's something worth checking.

 

Try the TPS adjustment. Ive solved many crazy problems on my car and others by adjusment. Its free and easy (if you have a freind help) and quick. A search will help with the tech stuff but if you have Qs or problems PM me Ill give you the #s and locations and the easiest way I have found to do it

 

+1 My car was doing the same thing, jerking pretty violently during any transition to on/off throttle at any gear/speed. Calibrating the TPS made it all go away.

 

I have the FSM. I will definately do that this weekend.

 

if the car was running good until you removed the UIM, then it's something you did.

 

Iv dun a lot of jobs on my car this week and i managed to solve the same problem as you.

Just like they say all i did to solve this is new o2 sensor and adjusted the tps (oh and just cause it was on the ramp i changed the spark plugs, thats all and its solved.

managed to solve 3k hesitation and bucking at low speeds with light throtal in 1 week woohoo, im a happy man.