Pulsating idle solved, ETM guilty

[atman100]

I posted on here that I had a problem with the idle ( S-80 , 156k miles , five cylinder, sending up code 2188 Bank 1 , Idle too rich, and improper voltage at MAF sensor ) in spite of replacing the MAF sensor ( Cardone from O'Reilly Auto ) and the 02 sensor forward ( Bosch, mail ordered, helped but did not get rid of the problem)
but the problem was a dirty electronic throttle module. I took the module out and cleaned it for an hour. The throat of the module is perfectly round and was mirror polished on this model. The butterfly valve inside it is slightly ovoid, oval shaped. When the motor is at idle, the valve is closed but air can still leak past two sides of the oval as it is purposely designed to not close the throat off completely. But the widest distance of those leaky edges between the valve edge and the throat wall is less than 2 mm, and over the years, hard black carbon builds up on the edge of the valve . No air gets past so the car burns straight gas to keep going. It idles poorly, idle that sputters until the computer revs it up and exhaust that smells like gas. That kicks on "Engine System Service Required' in the message window. The O2 Sensor gets a coat of black soot, the car surges and struggles at take-off and bucks when decelerating. I spent for a new MAF, air filter, and an 02 sensor but what was need was the cleaning ($20, includes new gasket for the ETM ) Disconnect battery so the car computer doesn't know you're taking something out of it Turn on ignition for a few minutes to let computer feel throttle position before starting, after cleaned ETM is re-installed . A brand new ETM would need VIDA software programming.