Just installed new Edelbrock 1806 AVS Thunder series. Car runs 100000times better. Idles good, but when I shut off the car now though it gargles a few extra times..is this from running too rich or lean, or is that a timing thing?
High idle RPM can cause dieseling too. Check for factory specs. The momentum of the engine after switching off the ignition still causes fuel to be drawn into the engine and the combustion chamber heat ignites the fuel. If you have an automatic tranny, you can try leaving it in gear and turning off the ignition. If it doesn't diesel then then you know it's the idle. But make sure your dwell and timing is set correctly too. Don't set your timing first if the engine is idling high. You get a false reading. Good Luck.