At idle my car sounds nice and smooth, but on my pocketlogger, my ignition timing advance jumps all around from 2.5-8.0 deg at idle. It basically makes a really rough graph. I've hooked up pocketloggers to a few other cars, and they're typically nice and smooth at idle.

Is 2.5-8.0 deg normal for my ignition timing advance at idle? For more info, at a steady higher RPM, my ingition timing advance says the same. For example, at 2500RPM, it stays at 34deg.

Also, what sensors does the engine use to decide when to advance or retard the timing?

^bump^

i have a laptop datalogger. i will check mine this am and get back to ya.