hi everyone i have an 89 caprice with a throttle body injected 350 small block. ive been having this annoying idle problem so ive tested all the sendors and their circuits the circuits all tested good. so to this point in time ive replaced the tps sensor, o2, map, idle air control valve and the egr valve. after all those it still doesnt idle right. well actually it idles great until the engine warms up the the idle gets very erratic and the engine almost dies. but those simptoms only happen in park/neutral it runs normally in gear. its also got code numbers 21, 22, and 32.
heres the break down for the codes.
21 throttle position sensor (TPS) bad sensor/short in wiring or possible bad ecm
22 which is the exact same as 21
32 exhaust gas recirculation (EGR) restricted vacuunm hose to egr solenoid or valve poor electrical connection, open or short in circuit bad egr valve or valve or defective ECM
and as i said ive changed the egr and the tps so i know the sensors arent the problem and tested all the wirng that runs them and it all tested good. the vacuum lines to the egr are also not restricted the only thing in the egr system that hasnt been changed is the solenoid that controls it. IF ANYONE CAN HELP AT ALL IT WOULD BE GREATLY APPRECIATED CAUSE IM STUMPED NOW THANKS.

 

I had the same issue with a diffrent car ended up being coil was bad

 

Hi,Idling problem when your car warms up to normal temperature mostly is due to temperature sensor problem.It send wrong signal to ECU.Good Luck