K2500 5.7L no codes misfire

[MrAnon]

98' K2500 5.7L:

Intermittent misfire

Started out with an engine light-P0339A-Intermittent Crank position sensor malfunction(replaced twice).

Still has an erratic misfire.

The only weird thing I noticed(by use of a scan tool) the RPMs will spike at 7500 RPMs(at idle). Should I be looking at a camshaft position sensor problem? Distributor problem?

Any help or information would be appreciated. Thanks.

[Jeremy-WI]

The rpm spike on the scantool would suggest it is still a problem with the crankshaft position sensor or its wiring. The VCM uses the crankshaft sensor for rpm readings because it gives a signal 4x per revolution versus the 1x per 2 crankshaft revolutions it would see with the camshaft position sensor signal

Check the crankshaft position sensor connector for loose pins and double check engine grounding points

[jonnik]

If I'm not mistaken, the engine computer governs the max RPM's in park to prevent damage.