1222 code but newer o2 and 30mpg

[SonomaGTLN2]

After fixing my ICV the idle is stable at 900 rpm but occasionally will drop and stall. The 1222 code comes on after idling for a while and while at a steady speed. I recently (within 5000 miles ago) put in a new o2 sensor. Two questions...1)can I adjust the AFM idle fuel mixture control? 2)I probed the o2 sensor port on the diagnostic connector and it is reading around 6.5 volts at idle...does this make sense to anyone?   I don't think I am running rich as I get 27-30 mpg consistently...

[roundel318]

After fixing my ICV the idle is stable at 900 rpm but occasionally will drop and stall. The 1222 code comes on after idling for a while and while at a steady speed. I recently (within 5000 miles ago) put in a new o2 sensor. Two questions...1)can I adjust the AFM idle fuel mixture control? 2)I probed the o2 sensor port on the diagnostic connector and it is reading around 6.5 volts at idle...does this make sense to anyone?   I don't think I am running rich as I get 27-30 mpg consistently...

not sure on the mixture, i think motronic takes over.
your mileage sounds decent, i had a bad ecu once that threw a 1222 after sitting idle for a while, it would also smell a touch rich, but not that bad.

[SonomaGTLN2]

I ended up unplugging the ICV and it idles up around 11-1200 rpm and no stall issue.  Has the very minor misfire sound that a lean condition might represent both with ICV plugged in and without...Really doesn't make much sense to me.  Car will stall if I remove the oil cap (no major vacuum leaks?).

[JoeDellio]

The fact you unplug the ICV and it revs up shows that it is working properly. 1222 is a bitch of a code. I just dealt with that code for like a year, and Ive read people still having it 2 years down the road. After replacing pretty much every sensor, fuel pump, plugs, wires, coils, every intake gasket, blah blah blah, I scrapped my engine because it had 250k and I was tired of dealing with it. The new engine still had the same code. I just replaced my fuel filter and O2 sensor for the second time and the code is finally gone.
The 1222 can be so many different things its a PITA to diagnose. Definitely start with your O2 though, because I only put 2000 miles on mine and killed it from having blowby in a cylinder, so dont be surprised. What kind of O2 sensor did you replace it with?

I dont think its an issue of running lean, as you would probably get a 1226 from the knock sensor for sure, which is another popular BS code. How are the visual conditions of your plugs and oxygen sensor?

[SonomaGTLN2]

Being an engine swap I did not have the pigtail for the O2 sensor.  I bought a generic 4 wire O2 (same a friend used successfully on his M42 swap) and wired it into the harness.  I don't know what sort of voltage should be showing up on the diagnostic connector (O2 terminal) but it doesnt change when the motor is revved.  I don't think the E30 M42 has knock sensors, but last I had the plugs out (but have not checked since the code has come up) they looked good...no carbon buildup and not white hot.

[SonomaGTLN2]

Checked the plugs and they looked clean but had a reddish tinge to the ceramic surrounding the electrode. Right at the electrode it was yellow/normal but the reddish color has me stumped...

[roundel318]

reddish meaning oil?

[SonomaGTLN2]

reddish meaning oil?

It wasn't soaked like you'd see with oil...just like a dusting of rust color. The plugs were not dirty looking and after 5000 miles it's lost less than a pint of oil...some of which was on the ground.

[roundel318]

If oil was making it in there, I presume it would get burnt off and not look soaked.
I was thinking small ammounts making it there and being combusted and exhausted leaving the reddish?
Oil loss doesnt sound too bad, how does the color of the oil look on the dipstick?