Thread: So confused... :(

Hey guys. Here's the problem... I have a 2001 Grand Prix GT (with the SS M90 kit), and I'm having a random non-start issue. My car will start fine for like 3 weeks straight, no problem, then all of a sudden it won't start. The first time it does it, the RPM will shoot up to 1000 or so, and it will die instantly. If I try start it again, it will just crank, and the RPM won't move. If I hold my foot on the gas, it will run, but as soon as I let off, it dies. Sometimes later that day, I'll try to start it, and it will fire right up. It just doesn't make sense.

I had an issue like this before, and after replacing the spark plugs, fuel filter, cleaning the MAF and cleaning/adjusting the IAC, it fixed it. It didn't happen for a while, then it started happening again. I changed the IAC from my old L36 throttle body to my current L67 throttle body, and it started up right away. I don't know if it was a coincidence or not. It was working fine for a bit, now it's doing it again. It's kind of hard to believe that both my IAC valves from both throttle body's are worn out, but I guess it could be possible. What do you guys think? Thank you.

check fuel pressure. Try to prime the pump for a couple seconds before starting it for the first time. Any stored codes when you do get it running?

I always let it prime for a few seconds before I try start it. After priming, my fuel pressure is around 40-43 PSI, so I don't know if that would be the problem. I don't have any stored codes at the moment, but I occasionally see a P0452 code. If I hold my foot on the gas and let it run for a minute, it will still die when I let off.

its an evap code bill. system pressure or leak. changing the pump might be the way to go

Anyone else have any ideas?

P.S. I'm deleting my EVAP system soon as well.

I really don't think this problem is fuel related. I bought a new IAC because my other one was giving values around 200 at idle and the pintle was way too long. So far, so good. The value is around 130 on a cold start an lowers down to about 30 on warm idle. No problems so far.

sounds like the fuel pump. the surge at start before dying is probably the residual fuel pressure from your last drive. prime the pump and listen for the hum next time this happens. you should get in the habbit of priming the pump before EVERY start to save wear and tear on the starter, pump, injectors, battery etc etc etc.

Vacuum checked the FPR?

Originally Posted by matt5112

Vacuum checked the FPR?

How do I go about doing that?

check the fpr by pulling the vacuum line off and see if its leaking gas. this would cause a dangerously enriched Air to Fuel Ratio. and pressure should drop, but dont quote me on it. i saw a thread where a dude had a gtp that was really hard starting, but ran fine. then he just replaced the pump anyways and it ran fine ever since. try a junkyard or amazon before you know for sure that it is the fuel pump

The line will smell like gas if its leaking a fair amount.

You can get a vacuum tester from princess auto.

Then apply 20 inHg to the FPR and see if it leaks.