On my scan tool when I view the data stream, the ignition timing reads anywhere from 20 - 25 degrees advanced all the time. Is this correct and should it fluctuate like this. I figured it should be as close to zero as possible on a stock engine
ignition timing question on 1998 Chevrolet 1500 Pickup
It wouldn't run hardly at all at zero degrees advance. What you see is probably completely normal. Don't make assumptions, especially don't act on them with cars. Unless there's an obvious timing problem, don't mess with it.