Oldsmobile/Buick Repair: Frustrating car trouble!, oldsmobile cutlass ciera, 1991 oldsmobile cutlass ciera

Question
Hello.I own a 1991 Oldsmobile Cutlass Ciera,6 cyl.,3.3L.I have had this car in 2 auto repair shops and no one can help me.Problem:Sometimes,upon starting,the engine idles much too fast.It stays that way for several hours.But other times it does not idle fast enough.Then other times I must apply the gas pedal just to start and keep it running.But sometimes it runs fine for several hours then it;s running poorly again.I had the TPS changed but it didn;t help.3 years ago I had new head and intake gaskets put on.I think it has a vacuum leak around the throttle somewhere.The repair shops say since it is not showing on the ECM what could be wrong and they say they were unable to help me.No,it does not overheat,but it sure is hard on gas!Plese give me some advice on this frustrating problem.Thank you in advance!

Answer
hi elizabeth..well i would certainly have to agree you have a vac leak.but it may not be on the intake .because an intake leak rarely goes away.this is an intermittant prob.which normally a intermittant prob is something mechanical that moves and seals and some times it won,t seal.there is only one part in the fuel system that fits that description.THIS WOULD BE THE IAC MTR OR IDLE AIR CONTROL MTR AND GUESS WHAT LIZ THE WAY THIS PART DECEIDES WHERER IT WILL IDLE .THAT,S RIGHT IT CREATES A VACUM LEAK WITH A LITTLE MECHANICAL SHAFT.IF THE SHAFT WEARS OR GETS OUT OF ADJUSTMENT.IT WILL IDLE ERATTICLY.AND THIS CERTAINLY SOUNDS LIKE THE PROB .GOOD LUCK AND PLEASE TAKE TIME TO RATE Y HELP  BILLYMAC