1991 grand am starts only when it wants

we recieved a 1991 grand am from my sister-in-law. when she gave it to us, she said sometimes it just doesnt want to start. she would disconnect and then reconnect the electronic fuel injection (atleast i believe thats what it was) and it would work for her but it hasnt worked for us! the electronic gas regulator was replaced but that wasnt the problem. there was an alarm installed by her friend and we thought maybe it was on a gas kill instead of ignition so we had that removed and it started up once but not a couple hours later. it starts about 40% of the time but that just isnt gonna cut it. please help!! we have 3 cars and none of them work!

I'm going to assume that the engine spins over fine.
What engine is in your car?
You need to find out what is missing when the car won't start...spark or fuel...that will lead you in the direction of the problem.
I have never heard of an "electronic gas regulator" on those vehicles....I'm going to guess that it was the fuel pressure regulator that was replaced.
Give us some more info and we will try to help you.

It seems to be a fuel injection problem. When the car does start with the air filter cover off I can get a clear look at what I think is the feul injection and I can see gas being sprayed in to the engine. The part that I believe is the fuel injection has been replaced by two different used parts and is not spraying fuel when car does not start. There seems to be no hesitation other than sometimes when when the air is on and the gas is floored the engine will back fire. Lost me at that. I can send pictures of the engine and the part that I beleive to be the electronic feul injector, also I believe that you are correct about the fuel pressure regulator. We have also replaced this sort of round valve and checked it for pressure. Im not sure exactly what engine it has the most I can tell you is that it is a feul injected four cylinder and when it starts it runs like a champ.

When the car won't start, remove the injector connector (2 wire connector on top of the injector) and jumper both terminals with a test light. Have someone spin over the engine and see if the light blinks.
Also, remove one of the plug wires from a plug and check for spark at the same time.
If there is no spark and the light doesn't blink, what may be happening is the crank sensor and module are bad.
You can e-mail me the pictures and I'll know what engine it is.

thank you, we will try that. what is an email address i could send you the picture at. im at work right now so it wont reach you until after 5:pm.

Just click on send GMMerlin an e-mail in my profile or PM me.

This is an old post, but..

Does the engine turn over when it won't start. If the engine doesn't turn over then perhaps the Neutral Saftey Switch is going bad.

If it doesn turn over then perhaps TPS or CPS is going bad??