The car is a 1982 Corvette and has 63k miles. My problems are cold and hot idle. When the engine is cold first start of the day it will idle around 1500 to 1800 RPMs out of gear until it gets a little temp built up and then drops down to within normal range. Then when it is at running temp in gear it idles at around 500 to 525 RPMs and is a little choppy, add a little gas to run it to around 600 to 625 RPMs and it runs smooth at idle. There are no problems when driving. I have changed the O2 sensor, the Temp sensor with the new type 2 wire sending unit that is recommended. The vacuum holds strong at 22 and does not jump around or fade. The TPS is set at .525 volts. The fuel pressure is at 12 PSI. Could this be an ECM problem that it is misreading the info it gets or could the TPS be bad and sending wrong info? Any other suggestions to look for would be greatly appreciated.

 

I am not familiar with the TBI set up on the 82s. However you might check to make sure that all of the passages are clean that involve the idle air. Did this problem happen all at once or did it happen over a period of time?

 

The problem was there when I got it, so I don't know how it developed But I will check the idle air to make sure that is good or bad. Thanks