About to put some gas and a match to my '92 Lumina Euro. Help ASAP!!

A few months ago, I had a blown head gasket on my '92 Lumina Euro. After I tore the engine down and put new heads on, the car would crank but wouldn't stay running. A mechanic I know hooked his computer up to it and it said that the ECM was bad along with the MAP sensor and the throttle positioning sensor. I replaced the MAP sensor and the car started to run better but would still cut off.
Today, I put in a remanufactured ECM (with a 1 year warranty on it) and a new throttle postioning sensor (also has a 1 year warranty) and cranked the car up. However, it still won't stay running. It will crank up then shut down after a minute or so. After so many times of doing this, it won't even start then. The car will just turn over but won't start. It will also pop and backfire when you try to get it running when it is at the stage where all it does is turn over.

I'm at my wit's end with this car. I just put $130 into this car today ($100 ECM and $30 throttle position sensor) in addition to the other money I sunk into this car (getting heads shaved, buying head gaskets, gasket kit, MAP sensor, new plug wires, etc.) and I can't take it anymore. I'm at the point where I'm ready to cut my loses and put some gas on this car and put a match to it. I'm hoping there is something that I am missing that you all can help me out with.
Please, tell me what am I missing? If you can't think of anything, I'm going to see if this car is fireproof.

The lil while its on is there black smoke coming from the exahust ? I had a Chevy Cavalier a 90 model it was doing the same think when i took it to the mechanic he said it was the carburator. Im not too sure if yur car has a carburator but like i said see if theres black smoke coming from the exahust thats what happened wit me it would also backfire. Good Luck

Did you check your fuel pressure?

Ok, I was just told something about a Honda Accord that was going through the same thing I am but I don't know if it would apply to me.
A friend of mine told me that he put a new computer in his car and when he cranked it up the first time, it ran but it cut off a few minutes later and wouldn't crank back up. He said that his computer had to be programmed before it could be used in his car.
When you replace the computer in the Lumina, do you have to program the ECM for the car to work or should it work right out the box?
This is really killing me. I would love to get my car running while I'm at home for Spring Break. I have some plans for it.

Have you hooked up a timing gun to it when it won't run and see if it even sparks, if it don't spark it should be either the ICM, crankshaft position sensor, or the wires between the crankshaft sensor and ICM

Now, what is the ICM?

Also, sometimes if you put your foot on the accelerator it will run for a second or two. Then it will cut off. It may backfire as well.

I remember reading in the Haynes book that when you put in the new ECM, you have to put in the MEM-CAL/PROM in the new ECM a certain way or it will be destroyed when you crank the car up. If that is destroyed, what would happen? Would the car not start then?

ICM(ignition controll module) did you put in a new PROM chip?? make sure theres a good connection to the computer. are the valves correctly adjusted?

I didn't put in a new PROM chip. I put in the one that was in my old ECM. Was I supposed to put in a new PROM with the new ECM?

you should always replace the prom chip when you throw in a new ECM. it dosen't make sense to me that the ECM and a bunch of sensors would suddenly crap out right after you slapped new heads on. if they worked before they should work now. did you do a compression check?, fuel pressure check?

I'll check on that this weekend and see what happens.

The ICM(Ignition Control Module) is mounted behind the coil packs on the front of the engine and has three connectors plugged into it

What about the timing chain? My dad seems to think that the timing chain might have been stretched and that's the reason the car won't start.

I just thought I would let you all know that it was the crank position sensor that was bad. I replaced it and the car started right up and has been running ever since.