i have a 96 blazer (mid-year) with a random misfire that started Sunday evening. I have replaced the cap and rotor didn't work.check the cam sensor and the coil tested fine. fuel pressure was 58 psi not for sure if that is too low not. I would like to know more of the main causes and how to check them, please! already have fuel injector cleaner add to the fuel did that when it started. plugs and wires not even a year old yet.

 

I have also been told that the crankshaft sensor could be it or a stuck EGR valve. any thoughts would help