I have an 87 bird with a 350 TPI. Some minor motor mods and tranny mods, mainly high performance stuff.

A while ago, the car starts having trouble. There is a whinning noise from the back, which is louder when the tank is empty, and you can stomp on the gas, and sometimes the car launches, other times it doesn't even know you've pushed the pedal. It occasionally stalls when I pull up to stop signs or red lights. And is very hard to start in the morning unless I turn the key on for about 5 or 8 secs and then try to start it. I was thinking fuel pump, but I checked the fuel pressure and its more than fine. Even with the car off and ignition on, there is 41 to 45 psi.
Any thoughts?

 

Have you changed the fuel filter lately ?

 

The whining is your fuel pump. Since w/ more gas in the tank it is submerged, it is going to get louder when you're running low on gas. It's always a good idea on these cars to try and keep at least 1/2 tank in there to help keep the fp cool. The reason you car is easier to start after letting the key stay on for a few seconds is b/c the fuel pump automatically primes itself that way. By turning directly to start it doesn't have enough time to build up pressure in the system. Leaking injectors or a bad check valve making you lose pressure too quick can also aggravate this problem. There is a test you can do to determine if you have a leak somewhere, but offhand I can't remember the procedure. check the tech articles and the archives.

p.s.- when you checked the pressure, did you try taping the guage to the windshield and driving down the road? f. press. at idle is only one component you need to check, by driving you're also checking to see if it's putting out enough volume for the engine.

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87 IROC-Z, 5.7, auto, 3.27, leather, !cat, Holley fpr, K&N'S, SLP 1-3/4" Jet-Hot coated headers, SLP .218/.224 .495/.502 cam, Comp 1.5 roller tip rockers, $uperPITAram, Edelbrock lower intake, Holley 52mm tb, Dynomax\Flowmaster catback. Coming Soon(?)- Fasttrack/Accell DFI

1989 Pontiac 20th Anniversary Turbo Trans Am - 161,000 miles, !cat, 9" K&N

 

It could be that when the pump gets too hot it stops working. I had that problem a few years back.