All right, this is kinda freaking me out...It's only done it to me a couple of times now, and when I get back in the car & start it up it's normal again...The tach will say 1100 rpm when it's idling at 750, and on shut down it will go to 500 instead of 0...Are my trailing coils going on the fritz or what?

 

that sounds like something got fubared my tac did that once though when my alt fried it would go to 900 or so when I had the key to "on"

 

so it turned out to be an alternator prob? that doesn't make any sense...unless it gets a battery volt input along with the trailing coil input?