Originally Posted by
white2001s10
That's normal when the engine is dying because of the misfires adding pressure to the intake manifold.
I think maybe your plugs got a little fouled from the beginning of the process, or the cold start.
40* is probably too high. Every combo is a little different but I'd guess the probable range to shoot for is 25* - 35* at idle.
Too much advance can make the idle less stable as well.
It'll just take some more time watching your scans and wideband to get a feel for what is happening with your idle.
Stay relaxed, take notes, spend some more time, and keep an eye on the plugs.
Once plugs are fouled I sandblast them and heat the tips with a propane torch to clean them back up for re-use. It's probably handy to have a couple of sets ready for the tuning process though. Cheapie plugs of stock heat range will do.