Greetings,

I have '99 SSE with 3800 series II NA engine that will misfire / run rough for several moments after a warm start, then it will rev itself up to around 2,200 rpm and smooth out - then run fine. A few times it would run so poorly it will stall, then I wait a bit for the engine to cool off more before trying again. It is not on every warm start, but the majority of them. When it is misfiring it really does not respond to the throttle.

Have not had the problem if the engine gets good and cold, but running errands around town is a pain.

Any suggestions? I was thinking to start with the coils, but wanted to ask here first in case others had already had (and solved) this issue. Found out a friend of mine is having the same issue with his LeSabre.

Start with the MAF. Give it a tap when running, does the engine stumble?

I'm having the same problem as RMMARTEL.I cleaned the MAF and that helped but sometimes it doesn't want to run right when warm.I've already changed plugs,wires and ICM.Maybe cam sensor problems?

Test your coils, and inspect the MAF real good. If you unplug it and start the engine, it will run rough for a bit then smooth out. If it starts better after that, the MAF is the problem. You will get a SES light doing this, but it will go away after you plug it back in.