1991 Park Avenue idle is to high!

[jdi226]

I have a 1991 Buick Park Avenue. Sometimes it runs like a charm, but some times its idle speed is 3000 rpm! What could be the problem?

[ks0309]

[check for vacuum leak at all hoses, also tps switch might be getting stuck (throttle position switch) or throttle body butterfly might even be getting stuck, spray a little lube on it

[Scott91]

My 91 is idling over 1000 rpm in gear while stopped. I am thinking tps is going? Any help is appreciated.