Hello,
I just bought a 98 GTP, it had the engine light on since I bought it and the car would hesitate when accelerating, it would vibrate then take off. The tachometer sometimes would drop to zero and the TCS Off light would come up, but the engine would still run. Turning off the engine and back on again would fix the tach issue. The car was also wasting a lot of fuel. It had 16.5liters/100kms (sorry I only checked it on metric). The car would accelerate normally when cold, but once it got hotter all of these problems got worse specially when giving it full throttle.
I took it to a mechanic to check it out, he checked the wires, plugs and filters. He said they were still in good shape. The engine code was for the crank shaft position sensor. I also did some research on the web for these symptoms and I found out that they were also related to the CPS. We just replaced the CPS and most problems are gone: tach won’t drop to 0 and it’s no longer wasting so much fuel, it’s at 14 liters/100km now. But I still have the power loss issue when hot. When I give it 100% throttle the acceleration is erratic, the engine revs jump while doing this. If I only give it about 75% throttle it has a more decent response and even more power than 100%. Again, none of these symptoms appear when the engine is cold.
The ECM doesn’t have any codes so we are not sure on how to proceed next. The mechanic is recommending me to change the plugs, filters and clean the injectors next, but I wanted to consult here first for any opinions on what should my next step be.
The car odometer says 97,500 kilometers not sure if someone tempered with that, but the rest of the car is in very good shape so I don't really doubt it. The seller also gave me an invoice in which they bought a new engine from the pontiac dealer back on 2002.
Hope someone can help, Thanks!
