My 98 Blazer keeps dying. Sometimes it will take a day or more before it will restart. It cranks over fine. MOST of the time cranking you can here the fuel pump. The pump has been changed twice but problem is still there. I have a diagnostic program on my computer and have connected to the Blazers OBD11 port. No trouble codes. I did find this - B1S3 02 sensor fuel trim with a reading of 99.06. I have no idea what this means. Everything else seems fine. I have been told that an ignition switch harness could cause engine to die like this. Any ideas. The Blazer is sitting in driveway and I am afraid to drive it.

 

Does the 'security' light on the dash illuminate when you are experiencing this problem?