At cold temps the idle goes up and down

I have a 1992 XJ with 169000 miles on it. As the title says at cold temps the idle goes up and down where she almost turns off. Now if I try to leave right away she spits and sputters for awhile. Once she warms up there are no problems. Any help would be great...

Thanks

Bo

I've had this problem before. Get a 9/16" socket and check torque on your manifold screws - you've probably got a couple working loose.

Since aluminum expands (relatively) more than iron/steel, pay attention to any screw that is holding down both aluminum and steel (the intake is aluminum, of course, and the exhaust flange is steel.) Aluminum expands twice as fast as steel.

Since the problem goes away once you reach operating temperature, the aluminum is probably expanding to "fill" the gap in the loose screw, which would be why the problem goes away once your engine is warmed up.

I don't recall the torque spec offhand (either 19 or 21 pound-feet, I think) but I've got FSM torque specs on my website, in the Tech Archive section. Link to my website in sig.