Pontiac Repair: 1990 Grand Am SE 2.5L turning over, but not starting., crank sensor, firing order

Question
I have a 1990 Grand Am 2.5L that i'm trying to get running.
I changed the spark plugs, spark plug wiring, and battery in hopes to get this to be an easy solution.
The car will turn over, but it will not actually start.
It is getting airflow through the car, as I can feel/hear exaust out of the muffler, foiling the idea that it might be a plugged up exaust system.
It will turn over for anywhere from 20 seconds plus, and they hiccup(I'm pretty sure it's backfiring, as it has spit small gouts of flame from the fuel injector array in the air cleaner)
I'm not entirely sure that the car is a 2.5L, the only thing I have to go on is that it is the rounded air filter, compared to the square one for he 2.3L.
We checked, and all plugs are sparking, all fuses are good, and the firing order is correct.
I would take it to a dealership and have them run   a diagnostic on it, but the car will not start for me to get it there.
The last thing I was thinging that it could be, would be the ECM.
The only issue with that, is that there are no pontiac dealerships near me, and I have no actuall proof that it is the ECM that is the problem.

I was wondering if you could think of anything else I could try to get this car running.

Thank you for any possible help.
Ps, the car hasn't been running for at least half a year, as the previous owner stopped using it when it wouldn't start in the extreme cold.

-D

Answer
Hi, is the fuel pump come? did you put new gas in? if you did all of this, check and see if the injector is sparying gas, you can do this by taking the cover off the throttle body the injector is in the top. if it is not sparying then this could be the crank sensor, or it has jump time.