the jerking is back

well I just finished a 700+ mile trip in the LTZ (3.8L) and the jerking/ chuggle/ fishbite, pain im my....is back:banghead: . The car did fine for the majority of the trip, but the last hour was horrible. I was lunging/ hesitating and the tach once again was jumping around a bit. I'm at my wits end with this!! Also noticed something else with this...the accelerator was harder to push and there seemed to be a lack of power as well. ARRRGH!! Does anyone have any idea what could be wrong and where I should start?? thanks

Take the TPS off and see if it's binding or something...might have disintegrated.

I agree with Jeff that it could be a bad TPS. What did you do prior to help eliminate the problem the first time.

I agree with Jeff that it could be a bad TPS. What did you do prior to help eliminate the problem the first time.

thanks guys. I'll try that and repost my findings. Hadn't done anything to elminate the problem before. Another member recommended changing out a few parts that seeemed to solve his jerking problem. They were the purge valve, purge solenoid, and vapor canister filter. I got all three parts, but my mechanic only installed one of them. I can't remember which of the three it was but it didn't fix the problem so I guess it's not important:eek: I was told that the filters I got (pack of 5) were not needed because my vapor canister was a sealed unit and they could not be installed. I wonder why they were listed as availiable on the website if it's not possible to replace them.

Do you guys know anything about these canister filters? are they replaceable or not? Also, do you think that if the problem is not in the TPS that it could be a bad vapor canister (unit)?

Could you give me a little information about the TPS? Location and instructions for checking/replacing? Also, how difficult is the job?

thanks again!!!! gw84

TPS is on the opposite side of the throttle body from the throttle cable bellcrank...has three small torx screws holding it on. It moves with the throttle plate shaft when you give it gas...that's why I was thinking you said it felt like the gas pedal had some resistance...it may have come apart and the engine will do strange things without proper input from it, it can't tell how much gas you're giving it and it freaks out.

Might have nothing to do with it, but seemed a logical starting point, given the symptoms...

This is for a v8 but same deal...right where the duct comes from the airbox to the motor is the throttle body, #16 is the TPS in this pic...

http://shbox.com/1/throttle_body_93.jpg

Do you have any CEL on or blinking? How long has it been since you tuned it up (plugs, wires, fuel filter, pcv) and if recently, what brand plugs and wires did you use? Worn out or bad plugs/wires will cause what you describe because the engine is under load at the torque converter lock-up threshold and will buck and chug due to misfires.

thanks guys! No CEL at all. I haven't had the plugs or wires changed since I purchased the car over a year ago. Same goes for pcv and fuel filter. I will see if the TPS is the culprit and will have the other afore mentioned items checked as well.

You said that the TPS is held on by 3 torx screws, is there anything difficult about removal/installation?? ...Anything else I should know? thanks