I have recently tracked an issue with my 18X reference signal on my 97 GP GT.
When scanning the vehicle with KOEO,my 3X ref. is 0,and my 18X has shown
values of 218368 numerous times after letting the engine rest for several
minutes.Since the engine is not running,I'm thinking the 18X should also be
displaying 0.The 18X is used for spark and injector timing below 1200 RPM.
The engine misfires below 1200,but as soon as the speed is raised above
1200 RPMs all misfires stop.I checked all wires from the CKP to the ICM,
and PCM for the 18X signal.no shorts in those.
Unplugged pin #4 (18X signal wire) at PCM and rescanned,still shows a value
with engine not running. Thinking about having pcm re-flashed,but may possibly
replace it. Does anyone know if this needs replacement or if a re-flash would
do the trick? I really don't think there should be any value other than "0",
when engine is not rotating.