truck will not start

What is your question?

I have a 1993 f150 with 4.9 straight 6. the truck has been sitting up for about 3 years. i cant seem to solve the problem getting it to start. i changed the fuel pumps, spark plugs and wires, distributor, and ecm. i have 60 psi fuel pressure. i can spray parts cleaner in it and it will start for a few seconds and then stops. if anybodies has any ideas of what i have missed or knows whats wrong please help. Thank you

What makes this problem better or worse?

N?A

How long has your 1993 Ford F-150 had this problem?

weeks