I bought my daughter a 2002 Blazer for her 16th birthday in Feb. She and I installed a K&N cold air cleaner and had high flow cat installed and changed the oil. It ran great. 3 months later she was having problems with it shutting down, wait about 10 minutes and it would start right up but had very little power while hot. The problem happened several times before the check engine light came on. We went to Autozone and checked the codes..random cylinder misfire. So we bought new cap,rotor,plugs and wires back to running great.

Last night she had just left the house, driving down the road and it just died. She tried starting it several times and finally killing the battery. She called and we tried starting by jumping. It would sound like it wanted to start but would sound like a pop in the intake. Being late we towed it home and put the battery charger on all night. I've checked fuel pressure..almost 70psi. Checked & cleaned battery connections, loose grounds, burnt fuse and vaccum lines but will not start. It did pop in the intake once like it was trying to start and does have spark. I removed the cap and rotor...looks ok but 1 of the screws was loose and that side looked dirter than the other side where screw was tight, I guess from sparking. I put rotor inside cap to keep them together and noticed that the gap from the pins in the cap to the tip of the rotor seems to be like a 1/4" between them which seems like a lot but it had been running like that because nothing looked broken. Being Thanksging day, I am going to pick up another set sometime tomorrow but don't think that is going to be the problem.

She does use the truck alot from high school to nursing school to hospital for training and to college at night. As you see she really needs it running. It gets a lot of use but only 70,000 miles. I've been online for several hours reading lots of post trying to find an answer. I'm starting to think maybe the ignition switch might be bad. Anyone had the same problem. Need HELP!
Thanks Guys!

I borrowed a friends gas gauge and rechecked fuel pressure because my release was stuck shut and could not release pressure. With his gauge the pressure was a little over 60psi but with the release pushed, the pump would run a couple seconds with gas coming out the release then shut off. Shouldn't the pump keep running to maintain the pressure?
Thanks

 

My first suspicion would be the fuel pump. Read this thread:
96+ Fuel System Diagnosis
Also, change the fuel filter.

 

The few seconds of gas is normal. Pump will run for 3 seconds then stop until it sees the motor turning.