Ok I've searched all over To no avail ... 1992 305 tbi on a cold start idle starts around 1500 like it should and comes down to about 750 like it should but the problem is if I don't turn the car off and back on once warm after driving a few miles the idle gets stuck at 1500 and surges in the 1300-1600 range untill the car is turned off and back on again ... it's almost like something is hung up ... tried swapping pretty much everything tbi base gasket tbi injector pods iac motor checked and replaced vacuum lines where needed ... does anyone have any ideas?? Really Considering throwing a carb on it and calling it a day at this point

 

Have you tried a different ecm (1228746).

 

Have you tried a SCAN TOOL to see what the commanded idle speed is?

Any other anomalies in the data stream?