I HAVE A 1990 626 WITH A 2.2L 130K MILES. THE IDLE BOUNCES FROM 900 TO 500 RPM IN PARK, WARM AND COLD. THIS CAUSES THE ENGINE TO DIE IN GEAR. (EC AT.) IT WILL IDLE OK FOR A WHILE THEN START TO BOUNCE. AFTER A LITTLE WHILE THE IDLE WILL SMOOTH BACK OUT AT ABOUT 900 RPM. ALL THE VACUM LINES WERE CHECKED ONE AT A TIME. NO HOLES IN THE BIG AIR TUBE. THE INTAKE AND IDLE AIR CONTROL VALVE WAS CLEANED. IT RUNS STRONG AND SMOOTH AT HIGHER RPMS. MASS AIR SENSOR RESISTANCE CHECKED OK. ANY HELP WOULD BE GREAT.
DOES ANYONE KNOW IF THE IDLE AIR CONTROL VALVE GETS A CONTINUOUS INPUT FROM THE ECM AT DIFFENT VOLTAGES OR DOES IT SIMPLY CYCLE ON AND OFF AT 12VOLTS. WHEN I PUT 12 VOLTS TO IT WHEN IT IS AT A SMOOTH IDLE, IT WILL BOUNCE FROM 900 UP TO ABOUT 1400 RPM

I AM GETTING NO CHECK ENGINE LIGHTS. IF I HOLD THE RPMS AT APROX 2000 THE ENGINE STILL HAS A 400 RPM BOUNCE. IT DOES SEEM TO NOT BOUNCE AS MUCH WHEN IT IS COLD. IT ALSO HESITATES SOMETIMES WHEN THE GAS PEDAL IS SHARPLY PUSHED. I AM RUNNING OUT OF IDEAS. PLEASE HELP THANK YOU