Like the title says engine cranks normally but won't start. So far I have checked and am definitely getting spark and fuel. This truck usually fires right off as in last summer it sat for a good 4 months and started like it had been driven the day before so this is very uncharacteristic of it........

 

Probably should add it is a 91 3.9 liter. I just checked codes and found something odd. Instead of getting code 12 and 55 I only got the 55 code.

 

does it sputter, backfire???? gas + spark should produce something. did you take the dizzy cap off and turn over to make sure the rotor turns and timing chain is functioning?

 

It backfired once. Took the cap off and looked but figured it was working since the plug was sparking when we checked that. Haven't taken the timing chain cover off. If something were off in there wouldn't I have piston to valve issues?