You said your check engine light is not on, but try this. Try to pull a code with the paper clip. If the check engine light flashes constantly, then it tells you no code. If it is flashing, tap on the AFM to see if it stops flashing, or if does not flash at all it probably is the AFM. I had the same problem, and what I found is that a short in the AFM will cause it to not start in addition to not allowing you to pull the code. When mine went out, I could tap on the top of it and sometimes it would let it crank. If I got it running, I could tap on the AFM and it would die.

Good Luck!

 

have u checked the timing? u can throw a timing light on it while somebody cranks it over.
i had a problem like this. it would just about fire then nothing and ended up the timing was screwed

 

Turns out that the cold start injector was stuck open, and now its only running on 3 cylinders