92 Park Avenue Engine Lopes

My 92 Buick Park Avenue engine seems to Lope at idle......meaning, I guess, maybe the RPM's may be going up and down. Haven't starting checking for problem yet, but will tomorrow. Not sure if it's a vacuum leak or maybe a fuel problem. Any suggestions ?

I believe I have solved the problem. I changed the Idle Air Control Valve, and after doing so, I found a vacuum hose that someone had disconnected. Someone had to pull it off because it won't fall off by itself. I believe the guy who performed the California Smog Test on the car recently did this hoping I would not pass the test.

Last time of a tuneup? Plugs, cap, rotor, wires, air filter etc...

Last time of a tuneup? Plugs, cap, rotor, wires, air filter etc...

Thanks for the response. I don't believe it's any of that. I'm starting to think that it might be the Idle Air Control Valve.