PCM losing it's Crank Reference?

[Webbs]

I have a 1998 Camaro and the car acts like it loses its Cam/Crank reference.

I can start the car but every few attempts the car will just burp out the exhaust while cranking. If I turn the key off and immediately retry to start it about 40% of the time it fires right up and runs great the other 60% of the time it burps out the exhaust again almost like it is 180* out. The crazy thing is it just started doing this out of nowhere. I have checked both sensors (Cam and Crank) neither have any damage to them. Checked crankshaft reluctor wheel run-out and I'm within tolerance at .015. Tried a new PCM with the same result. I am soooooo at a loss for ideas here. Anyone seen or heard of this problem before?


W~

[joecar]

Check if crank reluctor wheel is loose.

Check crank end-play.

[Webbs]

Check if crank reluctor wheel is loose.

Check crank end-play.

Checked both when I had the engine out to check reluctor run out and the reluctor is good and the end play was well within tolerance.

W~

[joecar]

You might need to look at CKP and CMP waveforms using an oscilloscope.