Random no start

[BigT]

I have a 98 LSC that seems to have a mind of it's own. It cranks fine but will not fire. It has fuel pressure but no spark and I have replaced the crank sensor. When it won't start it cranks quickly and the anti-theft light blinks. It may not start for a whole day or only an hour it doesn't matter time of day or temperature. When it starts it runs fine but did stall once while I was slowing down for a light then refused to start. Anybody have any ideas?

Thanks,
Tom

 

[DLF]

Have you checked for codes?

 

[BigT]

As of today no codes.

 

[Sapperfire]

Tps?....intermittent electrical failures are a PITA to track down sometimes, check the usual...injector pulse, spark, maf ect ect

 

[BigT]

I get a rapid flashing of the anti-theft light when I try to start it. I have fuel pressure but no spark. Originally had anti-theft codes but they were cleared when the shop thought they had fixed the problem with two bad ground wires on the steering column. It will run fine when it starts but may stall and refuse to start for no apparent reason then start a short time later with nothing being touched or changed. Does anyone have a wiring diagram for the anti-theft system?