Hello everyone. I still have not figured out the issue with my 2000 SS. I originally replaced the fuel filter then fuel pump. Since I replace the pump issues have got worse. Prior to all of this I had a high idle issue. No check engine light. But I replaced the MAP sensor, the MAF meter, IAC valve, TPS, and coolant temp sensor. Idle returned to normal. Drove it for a couple months. Then It died. would restart but not stay running. I towed it home and replaced the fuel filter. Ran better but had a stumble while climbing a grade as it has had for a long time. So, I replaced the fuel pump and matters got worse. It starts but if I let off the throttle it will slow down and die. I tried another fuel pump and replaced the fuel pressure regulator. Run issue is the same, but now sometimes the fuel gauge works. Sometimes it doesn't. And it just doesn't want to run right. If I keep on the throttle at around 1200rpm or higher it runs with no misfire. But as soon as I let off the throttle, it dies. I'm not currently driving it until I figure this out. I've sprayed carb cleaner all around and find no vacuum leak. I really need help here. Still no check engine light. and as I said before, things got worse after replacing the fuel pump. Twice. Any help is much appreciated. Thank you all.

 

I've had MAF sensors go bad after very little use.

 

I know theres no check engine light, but do you have a way to scan the engine sensors while running? Without seeing what they're reading, you could just be doing more shooting in the dark replacing parts.

Odd, I had one too and figured it was my bad luck. Had a 99 GTP that made it almost 100k on the stock sensor before it started randomly acting up. Bought a (relatively) cheap aftermarket that didnt even make it 2 oil changes before it completely failed (zero output across the board).

Ended up sticking the 85mm external off my monte on it (some OEM LS sensor) and never had issues again.

 

I borrowed a fuel pressure gauge and it showed zero pressure from shrader valve on fuel pressure with ignition on engine not running. I removed the gauge and cycled the key again, could hear the fuel pump run then stop. I pushed on the valve on fuel pressure regulator with a screw driver and a very small amount of fuel trickled out. No pressure. Would a faulty fuel pressure regulator do this? I plan on checking the connections on the fuel filter again. But, as I said before it ran better after replacing the filter but still had a slight stumble climbing a hill. So, I replaced the pump. Matters got worse. Just doesn't want to stay running. So, I swapped out the pump again. If i try to start it without touching the accelorator it starts up but rpms drop and it dies. I haven't been able to find any vacuum leaks. It really seams like a fuel problem. Especially since everything got worse after replacing the pump. I really need some help here. Thank you.

 

Not just you, I've had that issue as has my brother (2001 GTP). Aftermarket L67 MAF sensors are awful. I'm with you on the LS based MAF, I have one with a LQ throttle body to install when I get around to it.

OP, try disconnecting the MAF sensor and then start the car, see if it runs better.

 

It seems unlikely to be the FPR. That would have to be beyond toast to be dumping basically every drop of fuel back to tank leaving nothing in the rails when you open that Schrader valve. However, they're cheap to replace, so I'd probably stick one in to certainly rule it out, but it really seems like a weak / non functional pump to have zero pressure and only dribbles at the Schrader.