the other dat my 89 5.0 trans am started losing power and then stalled.
I took it to a mechanic and he said it just needed a tune up which he did along with changing the fuel filter at my request. two days later on a drive in the country it lost power on the road and I had to pull over. when I tried to pull away it stalled. even in neutral the engine wouldn't rev over 2000rpm.
while waiting for the tow truck I tried to start it again and it turned over but wouldn't start.
does any one know what's wrong. a friend of mine suggested the fuel pump and It feels like its running out of gas when it loses power (also runs really rough)

 

Get a gauge and hook it up to the fuel rail. It's the only way to tell. The only other thing I can think of with lack of power, and unable to rev is a clogged cat.

I had MAF problems that were similiar to what you're experiencing, but just not the rev'ing part.

 

I'd get a hold of a fuel pressure gauge (I believe parts stores rent them, if not they're approximately $30-$40). Check your fuel pressure when it stalls. With your key in the "on" position you should have something like 40-45 psi. With the engine running at idle you should have about 37 psi and it should rise when you snap the throttle open. (These are the specs for TPI if I remember right)

If your fuel pressure is lower than those specs you either have
A) a failing pump (most likely, especially if it starts working after a cool down period.)
B) a fuel pressure regulator bypassing too much fuel back to the gas tank therefore lowering the pressure at the fuel rail (less likely)
C) an electrical problem of some sort that is intermittently reducing the voltage available to the pump (faulty FP relay, faulty wiring. I'd say this is the least likely especially since your oil pressure switch acts as a backup for the fp relay)

EDIT (I'd agree that a plugged/partially plugged cat is a possibility as well)

 

He's on the right track here. Check the cat after it stalls and see if it's glowing red. If it is, you just found your problem. Don't forget to check the PCV valve. I've seen them drop a car before. It was only once, but I saw it,lol.

 

If you rule out the clogged cat, and go back to fuel pump...

1) crawl under rear, get ear as close to tank as possible, and listen while someone turns key to on - you should hear the pump prime.
2) if don't hear it prime, it may be the pump relay - try replacing that.
3) if relay doesn't help, try connecting the orange wire in the relay wirepack to the grey wire in the relay wirepack, then listen for pump again. If this makes pump run, when all else failed, then the oil pressure sending unit is bad - replace it.
4) if none of this works and pump won't run, you need a new pump.

I have a relatively decent post on the joys of replacing pump - search my posts for it. I've done 2 pumps this year (2 different cars) - get ready for the time of your life!

 

you might also want to check ignition module. they can break down under heat

 

this garage gave it back to me after a tune up and a changed fuel filter and pronounced it fixed. I wonder if they are scammers, incompetent or what?

 

More than likely not, but they dont drive it for more than the 2 mile test drive, so if it doesnt give them any trouble, they consider it fixed. If you want them to really check for it, theyll need to drive it or let it idle in the shop for a while and then take it on a long test drive to verify your problem. Having beena line mechanic, we usually tried to get a car in and out as fast as possible. If I was told to "tune up" the car...thats just what I did and sent it on its way. If you tell them it needs to run for a while before it does this, theyll more than likely spend a bit mroe time trying to verify the problem.

 

that was it. one of the fuel injectors was shorting out when the car heated up.
it ran ok when it was cool but after an hour it would start to run rough and eventually break down. they said when they took out that injector the car ran fine again. thanks to every one for the help and suggestions, it made a big difference.
p.s. i'm totally broke now!