My car will sometimes just jolt while driving. This isn't while shifting either, it feels like a real hard shift, but the car isn't. What can this be? Also my TCS and tach will go out at the same time when this happens and sometimes when it doesn't jolt. car drives fine otherwise. 00 GTP.

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00 GTP Daytona

Nobody has any ideas? I would to fix anything now before it gets big.

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00 GTP Daytona

Sounds like an electrical gremlin somewhere. This will be a pain to find, it appears.

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One Big Ass Mistake America

I think that it might be, the TCS and tach go out at the same time too. Where are some of the tranny electronics? Grounds, sensors, etc...

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00 GTP Daytona

Sounds like a bad CPS to me; here's a write up: http://mykidz.net/GTP/CrankPosSensor.shtml

What would the tranny jolting have to do with the CPS? I should add that the tranny jolts once every few days and the tach/tcs issue is a seperate independant problem but they did go out one day at the same time when the tranny jolted once.

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00 GTP Daytona

From what I've read, the tach and TCS going out at the same time is usually a bad CPS. As for your tranny problem, one possible culprit is the Pressure Control Solenoid: http://www.automotiveforums.com/vbullet ... p?t=899929
Then again, it could be that the "jolting" is being caused by the loss of reference signal from the CPS; I'd replace the CPS first, and go from there.

I haven't had a chance to look at anything yet but the car is getting worse. The strange thing is that now the car will jolt repeadedly only going up hill when I try to accelerate say 3K rpm and above. The car also sounds like it is missing at 3K, I'm working on that. I just replaced the front plugs and the electrode is about gone, so there probably hasn't been any maintainence on the car in its 106K mile life. The rears will be done ASAP. The only codes that the car was throwing that would be a concern is for a random misfire. Are these two problems related, the car missing is causing the tranny to act like this. Its a completely stock 00 GTP.

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00 GTP Daytona

Your random misfire code could just be bad plugs and wires; after replacing them, clear the code(s) and take it for a test drive. OBD II systems have a two trip memory, so if no codes come back after three trips, you should be ok. Given the mileage on the engine, I would think about replacing the LIM gaskets (especially if they are the black plastic ones), with the aluminum ones from ZZP or the GM dealer. They're known for failure on higher mileage cars, and usually wipe out the engine bearings when they let go. (Been there, done that)

Justin I have the same problem. And for a while I thought it was the tranny but it could be just the plugs from what I have heard too. I work at a GM dealer and a tech asked me if I pretty much do a brake stand, will it jolt like driving? And I answered yes it does. He said to start with the plugs before concluding to the tranny. Plus my tranny only has like 10K miles on it.

I will have to look into the CPS but I dont think its that. I dont have any check engine lights either but I havent scanned yet either.

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http://WWW.AZGMPERFORMANCE.COM

If you find carbon tracking (black lines) on the plug insulators, or grayish white spots on the ignition wires (arcing), it's time to replace the wires as well.

Thanks guys. Hearing that its probably the ignition is a big relief. I'll go ahead and replace the wires and coils (corroded contacts) and I'm not sure about the LIM gasket being replaced or not. I'll also go ahead and put a new filter in the tranny since it probably needs it.

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00 GTP Daytona

You're welcome! If you look at the engine where the LIM meets the cylinder heads, you should be able to see the gasket edges. If they're silver gray, you've got the aluminum ones. On the tranny, just change the fluid and filter, don't flush it!

Any way to tell that they are bad? The oil looks good. I've done LIM gaskets before on my old 89 2.8 Camaro where you have to pull the pushrods too.

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00 GTP Daytona

You wouldn't see it without pulling it apart, but the black plastic ones usually fail around the water jacket ports. I replaced them on a '95 Park Ave that had only 74,000 miles on it (I'd just bought it for my dad for Father's Day), and sure enough, they were just starting to separate (with green antifeeze in the engine). Thankfully I'd caught it in time.

I guess that I should jump on top of that then.

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00 GTP Daytona

Look at it this way: It's a good excuse as any to replace the injector o-rings, fuel line o-rings, valve cover gaskets (big oil leakin' o-rings), coolant elbow(s), etc. Preventative maintenance is the key to keeping the engine fire gremlins away...

This is getting away from the tranny thought but...'

I changed the plugs and did one at a time. Now the car is shaking, it sounds fine though at idle. I haven't driven it, just up the driveway and back. All of the connections are good at the coil and plug. It didn't shake like this on the way home either today before I did the plugs. What could it be. I'm going to pick up some wires tomorrow and see about getting some coils too.

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00 GTP Daytona

It's possible you got a defective plug or got some dirt on it, or one or more of the wire boots is torn, and the wire(s) are arcing out. If it still acts up after changing the wires & coils, check it for misfire codes. Did you see any carbon tracking on the old plugs?

What's carbon tracing?

The plugs were way overdue for a change. They were bad.

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00 GTP Daytona

Carbon tracking looks like dark lines that are permanently etched into the spark plug ceramic insulator, and inside the spark plug boot. The spark burns a path on the outside of the plug instead of firing through the center electrode, causing the cylinder to misfire. When you see this, you need to change the plug and the wire at the same time, or the old wire will leave carbon tracking on the new plug. If you see carbon tracking on the coils, replace them as well. Apologies for going off topic, but sometimes a tranny gremlin is actually an engine gremlin in disguise...

I still got problems and this is getting away from a tranny issue so I'll make a new thread.

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00 GTP Daytona