Faults:

The transmission failed at 50,000 miles. I thought I had somehow caused the problem because I had replaced the ATF with Mobil 1 synthetic at about 5,000 miles and then again at about 45,000 miles. Although I was very careful about keeping everything clean, I thought maybe a piece of crud had gotten into the shifting modules. So anyway, I had the transmission rebuilt by the Pontiac dealer where I bought the car. It worked great until about a year ago (mileage unknown). When I pressed hard on the accelerator at about 50mph, the transmission would not immediately drop out of D into 3rd. Instead, the engine rpm would pulsate violently. However, the car could be accelerated slowly without any problem. I took the car back to the dealer and they told me that the plug wires were bad and also that one plug had failed. They also replaced a fuel filter. I'm not sure what they "actually" did to fix the problem because I had just had the plugs replaced a few thousand miles prior to that. The car has begun doing something similar since 100,000 miles in that it hesitates and pulses slightly when shifting from Drive to 3rd under acceleration.

My current problem is a noisy supercharger drive belt tensioner. I have replaced it twice with aftermarket tensioners from Auto Zone and it still makes a racket at idle (in Drive). At the slightest increase in RPM, the noise goes away. After reading some of the comments made by others, I'm beginning to suspect the supercharger drive coupler. Any ideas?

General Comments:

The car is still very quick even at 105,000 miles and gets great gas mileage. About 23 around town and 34 on the Interstate.

I wish the seats were more comfortable on long trips.

I can't say that I am happy with any GM dealer repair. If you aren't VERY knowledgable (I'm not) about the newer computer controlled cars, you are at the mercy of the dealer repair shop.

Faults:

On my previous 94 Grand Prix SE 3.1L at 165,000 miles, my head gasket blew and the head cracked in half. Other than that, just regular maintenance, (brake pads, Disc and exhaust.) The 94 ran for over 240,00 miles before I let my son have it, so he could trade it in for a 2004. It still ran like a top.

On my present 98 Grand Prix GTP, at 131,000, I am getting ready to replace my SC nose drive, instead of rebuilding it. The nylon type bushing was wearing, and I let it go too long, and now it is affecting my bearings. You can replace the bushing yourself, but to do the bearings, you need a Hydraulic press. I feel it is cheaper to go to ZZperformance.com and buy a completely rebuilt nose for $200 with better than OEM parts. If you plan to put a smaller pulley on, buy it from them and they'll install it for free when you buy the nose. Also, their bushing is of better material than that of the OEM one, and will last way longer.

General Comments:

As for the 98 Grand Prix GTP Coupe, I would not hesitate to buy another one. That car has surprised a lot of other newer and older muscle cars, including a newer Vette. From a dead stop at a light, he never got closer then my rear passenger window. He was winding it out for all that it was worth, and I never noticed I had it in 2nd all the time.

Being have been in the automotive building trade business for over 20 years, and dealing with the factories directly, there is no perfect model, brand or car. Each model, no matter how good it is, you are bound to get a batch that will have problems in certain areas. This goes back to the fault of quality control inspection, where the parts was made and/or assembled.