99 lumina jerking

[sptyler]

I have a 99 lumina 3.1 engine v6. It starts to jerk after you have driven it for over an hour or so. It jerks when you accelerate up hills or slight inclines or sometimes on straight roads, but mostly accelerating up a hill. The jerking is intermittent you never know when it will start. If you take your foot off the accelerator pedal it stops and when you push down on the accelerator it doesn't do it as bad but can feel some slight jerking. I have driven it in overdrive and just drive and it still does it. I have had the plugs, wires, fuel filter, you name it it was done at the dealership and it still doesn't run right. I spent $798 dollars at the dealership on the above items. So I'm leary about taking it back to the dealership. Could this possibly be the TCC solenoid acting up??

[maxwedge]

Originally Posted by sptyler

I have a 99 lumina 3.1 engine v6. It starts to jerk after you have driven it for over an hour or so. It jerks when you accelerate up hills or slight inclines or sometimes on straight roads, but mostly accelerating up a hill. The jerking is intermittent you never know when it will start. If you take your foot off the accelerator pedal it stops and when you push down on the accelerator it doesn't do it as bad but can feel some slight jerking. I have driven it in overdrive and just drive and it still does it. I have had the plugs, wires, fuel filter, you name it it was done at the dealership and it still doesn't run right. I spent $798 dollars at the dealership on the above items. So I'm leary about taking it back to the dealership. Could this possibly be the TCC solenoid acting up??

Welcome to AF, what you describe could be a classic engine misfire, bad injector one possibilty, the tcc could be " chuggling from wear, or the tps could be causing it to lock and unlock, issue here is how about $800 spent and the same problem. If you brought it in for this issue, drop it in their lap and speak to SM, either they fix it or refund your money as a result of " ineffective" repairs.

[sptyler]

I forgot to mention that it usually does it between the speeds of 45 to 60mph and it doesn't always do it everytime during these speeds. Plus I get no error codes or engine light on the dash.

[richtazz]

Like Maxwedge mentioned, bad injectors will cause what you describe. At the speeds in which it's happening, it could be a TCC lockup issue(as that is the TCC lock-up threshold), but if it's that bad, the stealership should have been able to pull a code on it. Bad injectors don't trip a code of their own, but will sometimes cause a random misfire or specific cylinder misfire code if only one injector is bad. I also agree that you should talk to the stealership service manager, as I would be insanely ticked off after spending $800 and my car was not fixed.

[gw84]

I had the same problem with my '99 (3.8L). It's only done it once (knock on wood) and happened when I was driving about 60-70mph. Does your car have a tach??

[sptyler]

No it does not have a tach. I went into town today and was keeping the speed under 45 and it did it once starting at 35mph. It is so intermittent never know when it is going to do it there is no commonality to it.

[gw84]

bummer, no tach. Whenever mine did this the tach would jump around a bit. I have no clue.

[gw84]

*Update* ('99 LTZ 3.8L) Drove the LTZ for over an hour yesterday. The shaking/jerking is back. I was driving home doing about 55mph. What should I do? Should I start cheap (plugs, wires, etc)? Also, is there anything that I should clean (egr or something)?

[richtazz]

Yes, start with regular maintenance items such as plugs, wires, fuel filter, pcv, valve, etc... if it's been a while since you tuned her up. You can also try unhooking the battery negative cable overnight, as this has worked in the past with people suffereing from what is described as "chuggle or fishbite" (a random jerking or mis-fire like hesitation near the torque converter lock-up threshhold speed of 40-60 mph.

[maxwedge]

Originally Posted by gw84

*Update* ('99 LTZ 3.8L) Drove the LTZ for over an hour yesterday. The shaking/jerking is back. I was driving home doing about 55mph. What should I do? Should I start cheap (plugs, wires, etc)? Also, is there anything that I should clean (egr or something)?

Typical ignition misfire symptoms, based on mileage if you are due for plugs and wires do it, but stay with oe AC plats, and someone's premium wires, also Delco. There are other conditions that can cause this but basic maintenance comes first, any cel?

[gw84]

Originally Posted by maxwedge

Typical ignition misfire symptoms, based on mileage if you are due for plugs and wires do it, but stay with oe AC plats, and someone's premium wires, also Delco. There are other conditions that can cause this but basic maintenance comes first, any cel?

Thanks guys, for the help! I'll take a look at the plugs tomorrow. If they're ok, I'll try the unplugging the battery cable, and see if that works. Max: what do you mean by "any cel"?

[maxwedge]

Originally Posted by gw84

Thanks guys, for the help! I'll take a look at the plugs tomorrow. If they're ok, I'll try the unplugging the battery cable, and see if that works. Max: what do you mean by "any cel"?

Sorry, check engine lite, typing skills are weak.

[gw84]

I'm still new at the abrev. on here No. I haven't had a cel yet (knock on wood). Just a jerky car after driving an hour. Would you agree with Rich. about unplugging the battery cable overnight, to see if that works?

[Blue Bowtie]

Disconnecting the battery could help, but it also just as easily may not, or any "improvement" may only be temporary. The integrator function of the PCM is suually fairly tolerant of changes, and will update the block learn with any parameters that are within the acceptable programmed ranges for feedback sensor inputs. Since you are not getting any MIL (Malfunction Indicator Lamp) the inputs are likely within an acceptable range, and the PCM has probably already "learned" any changed operating parameters. Disconnecting the battery MAY clear the tables and force re-writes, but the data may end up being about the same. It can't hurt, so long as you do not have the Theft-Loc on the radio enabled and the TDM does not lose any transmitter codes. You would actually be better off by removing the PCM power fuse(s) and leaving the battery connected to back up all the other devices.

I'm guessing it's time to take a close look at the ignition and fuel delivery. Usually, ignition events are closely monitored by the PCM, and misfires are detected easily. That leaves the fuel delivery system, which is actually not monitored that closely by the PCM. Poor injector flows, poor spray patterns, high propagation times for injector pintles, and other fuel delivery problems aften go unreported by the PCM until they cause a more significant problem.

[gw84]

Originally Posted by Blue Bowtie

Disconnecting the battery could help, but it also just as easily may not, or any "improvement" may only be temporary. The integrator function of the PCM is suually fairly tolerant of changes, and will update the block learn with any parameters that are within the acceptable programmed ranges for feedback sensor inputs. Since you are not getting any MIL (Malfunction Indicator Lamp) the inputs are likely within an acceptable range, and the PCM has probably already "learned" any changed operating parameters. Disconnecting the battery MAY clear the tables and force re-writes, but the data may end up being about the same. It can't hurt, so long as you do not have the Theft-Loc on the radio enabled and the TDM does not lose any transmitter codes. You would actually be better off by removing the PCM power fuse(s) and leaving the battery connected to back up all the other devices.

I'm guessing it's time to take a close look at the ignition and fuel delivery. Usually, ignition events are closely monitored by the PCM, and misfires are detected easily. That leaves the fuel delivery system, which is actually not monitored that closely by the PCM. Poor injector flows, poor spray patterns, high propagation times for injector pintles, and other fuel delivery problems aften go unreported by the PCM until they cause a more significant problem.

Wow. That's a lot to take in Here's my abbrev. question of the evening: what is TDM? I guess I have a lot of options to weigh. Thanks all for the great advice. I'll talk to my mechanic about the situation and see what his thoughts are. I just hope he doesn't go into "...well lets start by replacing the____, then if that doesn't work will put a new ____ in..."