Engine Performance problem
1996 Pontiac Firebird V8 Two Wheel Drive Manual 144000 miles
I have a 1996 Firebird Formula 5.7litre w/ 6spd manual tranny. Six months ago I replaced all of the ignition components -- the optispark, the coil, everything. This was primarily a preventative measure because I was preparing to drive the vehicle cross-country. The PCV valve is also new. Cold air intake system. Full custom exhaust system, but the cats are probably 4 years old. I do all the work myself -- I'm not a mechanic, but I know this particular vehicle like the back of my hand.
About a month ago, I was merging onto the freeway, and when I hit about 3800RPM, the car stalled. I pulled over to the side of the freeway, tried starting it again, and it would turn over great but wouldn't fire. I quickly checked all the fuses, and finally gave up and called a tow truck. Five minutes later, I turn the key, and the car fired up immediately, like nothing was wrong. I went to pull out into traffic -- babied it through first, then got into second and mashed it. Again, the car hit about 3800RPM and stalled. So I pulled over, and it wouldn't start. Gave it a few minutes, tried again, and it started great.
When the vehicle is idling in neutral and I mash it, the engine will nail the 5800RPM rev limiter and everything is fine. But any time there's resistance on the drivetrain (i.E. In gear, on pavement) the car stalls around 3800RPM. The other day, I went to the Dr's office, and when I came out, the car would turn over but would not start. So I opened the schrader valve and released the fuel pressure. Turned the key, and the car fired right up as though nothing were wrong.
I'm going nuts here! I'm thinking it's something in the fuel system, or possibly in the ECU, or maybe even a relay? What can cause this? I have emission testing coming up soon, and they will reject the car if it stalls on them in the middle of their tests! Please help!
have the same problem?
Thursday, March 12th, 2009 AT 5:45 PM