ok here we go i have a 2003 blazer 4.3L engine turns over and it will not start so i checked the spark( good) checked the timing( good) hooked up a scanner(no codes) checked fuel pressure (64)when pump comes on when pump turns off it drops to (57) and holds this morning did a compression test they all run between 135 and 150 psi when i removed the compression hose from the plug holes i had gas on the tester.could it be mass air sen,any of your ideas would be great.thanks

 

Unplug ur MAF and find out!

 

How long did you let it sit with the fuel pressure gauge on? It should not go below 55 for 10 minutes. When was the last time it had a tune up? Are all of the lights coming on with the key in?

 

all the dash lights come on it was tuned up about nine months ago plugs,wires,cap new fuel filter when i did the compression test put the plugs back in the wires had spark to all the plugs