m20 idle issue. CEL code 1222

[hooken m]

https://fbcdn-video-f-a.akamaihd.net...9616aed07e15ec

Car is 91 325i.

I am absolutely stumped. The check engine code I get is 1222. There is not a single gasket, hose, or anything vacuum related that hasn't been changed. I've done 3 smoke tests so far none showing any leakage from anywhere. Bitch tube, valve cover gasket, dip still orings/gaskets are all new/good. Tps is adjusted properly, icv works properly, afm rebuilt, injectors rebuilt, new fpr, new distributor cap,rotor, and ignition coil. Almost anything I can think of has been replaced. When driving, the car performs extremely well. Help me please it's driving me crazy

My car started doing this about 2-3 weeks ago out of no where. never had any kind of idling issue like this before.

[ELVA164]

If all of that is definitely good, I'd say ECU. My car also idled perfectly until one day it just...didn't, and it turned out to be a bad ECU. Much less common with the single-board ECU but not impossible.

I'm assuming you mean "adjusted properly" by a professional? No offense if you did it yourself, but just for diagnostic reasons.

[hooken m]

yea i got a buddy who is going to lend me a spare 173 to test. i even double checked the TPS today. i checked for continuity in the rest position, partial throttle, and full throttle position also checking for resistance as well. the TPS is definitely adjusted properly.

[ELVA164]

How did you test the ICV?

[hooken m]

for resistance between the terminals, take the hoses off turning the key to make sure the flap opens or closes, forget which one it was supposed to be, and it buzzes. thats as far as i know about ICV testing.

[Gregs///M]

Maybe put a multimeter on your o2 wiring at the DME, check to see if the values are within range.

Once helpful thing that I use is in the Bentley manual there is a DME test section. It outlines each pin of the DME and what its electrical state should be. This way, you test the sensors and their wiring. If you find something out of range, you can focus on that.