So, we took my wife's 97 tj to get groceries yesterday. When I started it after shopping it ran rough and backfired through the intake a couple of times, but then it straightened out and ran fine back home. Then this morning it started but wouldn't idle. She could keep it running by keeping it revved up but as soon as she let off the gas to put it in gear it would die. I read a bunch of post on similar backfire problems but not quite the same. I feel like I should know how to go about trouble shooting this, since I've maintained all my vehicles all my life and even taught high school auto shop 40 years ago, but I'm at a bit of a loss where to start. Maybe I'm getting too old and losing my memory I don't want to just start throwing parts at it. My guess is that it's something to do with the timing; maybe a sensor or it needs a new cap & rotor? Anybody have experience with this type of problem or can point me to a link that could help?