Pontiac Repair: FIERO, vacuum leak, possability

Question
I KNOW YOU SAID NOTHING OLDER THAN A 90 BUT IT'S ELECTRICAL SO HERE GOES. AN 84  4 CYL. FIERO, ITOOK OUT THE ENG. AND TRANS. TO PUT A NEW CLUTCH IN . WHEN I WENT TO START IT I GOT A CHECK ENG. LIGHT. IT WAS FOR THE TBS, I GOT ONE AND INSTALLED IT. NOW NO LIGHT BUT THE ENGINE IDLES AROUND 4 GRAND. I INSTALLED A NEW IAC, STILL GET THE HIGH IDLE.        I CLOSED OF THE PASSAGEWAY FOR THE AIR TO GO PAST THE IAC AND THE IDLE DROPPED DOWN TO ABOUT 1 GRAND.                     ANY IDEAS ON WHAT COULD BE CAUSING MY PROBLEM

Answer
Hi Bill.

You replaced a TPS? If this started after the TPS was replaced My guess it either it's the wrong one for the car or it's installed wrong. The TPS is a sensor input to the engine computer it tells the computer how far you have your foot on the gas. If it's sending the wrong reading to the computer telling it you have the throttle depressed and you don't it will command the idle up. The other possability is a BIG vacuum leak. But I doubt it if you block off the IAC passage and it idles okay. That would be my first 2 guesses but with out a scan tool to see what is going on it's just a GUESS. Good luck :)