This truck is weird. Runs fine. It has a los of power at times doesn't cut out or miss. The rpms will be around 4/5000 and will be moving but not with power. This is from the go. Now the issue is randomly. Will park n go and start it back up. Will turn over basicly start then shut off. Will continue doing this. security light will blink if u continue turning it over. Does not have chip on key. Getting. Fuel and spark. Unhooked battery doesn't change nothing. Replaced plugs wires fuel filter. ignition module. Rotor and cap. A few other sensors. then five,ten hour later will start and run fine for a week two weeks month. This been ongoing for four months. Any ideas???

 

Yes, the ignition switch. After all the problems with my 99 blazer, i ve since found out this is the achilles heel of these trucks. Lots of circuits run thru this thing, including the passlock system and a bad one will give the exact symptoms you describe. It is located in the column and will cost about $100 depending on brand.
Check out my previous post. Good luck, Steve.