My 2006 cobalt won't start. It turns over, the fuel pump is working, there is spark. The ignition coil is fine. A mechanic spent 2 hours on it and couldn't find any cause. The check engine light is on, and was on the day before it stopped working, but not the day of. The check gas cap message had also been displayed twice in the days leading up to it. We are out of ideas, as is our mechanic. Any suggestions of what could be causing the problem are welcomed. Thanks!

 

Do a fuel pressure check. Having fuel is not enough. You need the correct fuel pressure.

 

Also check injectors for pulsing. Might have theft deterrent problem keeping car from enabling fuel injector for start.

 

the fuel pressure is fine, we checked it. We also checked the injectors with a stethoscope

 

Maybe a compression check is in order? a valve not seating could be not allowing the start... just a thought...

 

+1 for compression check

if your fuel pressure was good, what was the pressure reading? you checked spark with a proper spark tester?