I purchased a 2004 ZR2 a week ago. I don't put much on seller stories but was told the proverbial little old lady was driving and it just stalled. They guy who I purchased it said he purchased it to repair it but lost interest. He put in a new fuel pump and new plugs and wires. So not being my first Blazer rodeo I checked the fuel pressure. 58psi proper bleed down. I added new cap and rotor. I also own a 2004 Jimmy ZR2 so I removed the coil and module assembly and it works fine in my jimmy. So now I have run my course. I am not educated on the passlock system and couldn't find specific information to tell if it is functioning properly. I might note the alleged little old lady didn't install the pioneer 7 inch stereo and amp which has wires everywhere so I suspect someone might have shorted something. Oh yes, I have a good OBD11 scanner and it shows no codes and using quick start did nothing.

 

Crank sensor bolt vibrated loose and worked it's way out just enough to stall.