helping to troubleshoot a co-worker's car:
98 Neon (auto and A/C) that has the "service engine soon" light lit.Hooked up my autotap, it showed a P0300 and P0301 misfire/cylinder 1.
tried to clear them, my autotap thinks the MIL is off, but it won't turn off, and my autotap thinks there are no more DTC's.
He's going to do the plugs - no one knows the vintage of them, so it's a good idea anyway... Plug wires all look good. Engine runs fine, if it's a misfire it's just enough to light the MIL.
One other thing of note - the belt for the AC squeals on startup and shakes the car pretty good at the same time, I'm wondering if that's being interpreted as a misfire?
or maybe if anyone has info on this TSB:
18-47-98 DEC 98 PCM - Symptomless Misfire DTC's/MIL ON