running rich

[FiendScurro]

Now that my car is mechanically sound (rack and pinion and power steering pump, drive axle, rear brakes all the way to new calipers) I wanna figure out why I'm running rich. At idle I'm sitting at -18. I was told that should be much closer to zero. Things I've done: 30k ago - plugs and wires, pcv valve, intake cleaned, maf cleaned. Last winter - lim and uim gaskets and metal elbows Recently - upstream o2, fender well intake, fuel filter, thermostat (stock temp).

Where should I head to solve this issue without throwing parts at it?

[00Beast]

How are you at WOT? The danger of having an aeroforce, etc is too much info that someone who doesn't understand the intricacies of EFI and PCM tuning doesn't know what to do with. When it's cold like I'm sure it is in NY, just like it's here in MN, the car adds fuel at idle to force a hotter burn, to keep the engine warm. This is within the range of the PCM's operating parameters as far as I'm concerned.

[SuperHbody]

Well first of all is that the Long Term fuel trim or the short term? If it's the Long term you are correct in saying it's running rich. That would indicate a leaky injector, clogged air filter, bad O2 or a bad fuel pressure regulator. If it's the short term I wouldn't worry about it, that's the corrections it's doing in real time. When diagnosing that stuff Long Term is what you want to look at.

[FiendScurro]

I don't have an Aero force... but In any case, a club member plugged in his scan tool and was monitoring while I drove. He says I am running rich according to the long term fuel trim. Where should I start?

I just cleaned and resprayed my k &n maybe 5k ago before I installed the fwi that I got used.

[SuperHbody]

I don't have an Aero force... but In any case, a club member plugged in his scan tool and was monitoring while I drove. He says I am running rich according to the long term fuel trim. Where should I start?

I just cleaned and resprayed my k &n maybe 5k ago before I installed the fwi that I got used.

First of all, and this is my opinion, get rid of that K&N air filter. I've started to notice quite a bit of problems with those filters in terms of the oil fouling out MAF's. Not to mention the reduced filtration for the sake of air flow but that is just my opinion. I'd check your MAF and see if you might have over oiled the filter causing it to gum up that MAF. After that, some simple fuel pressure tests can tell you what's going on. Did you replace the O2 sensor with genuine GM parts?

[FiendScurro]

I swapped out the maf with another working one and it was the same. Yes the o2 was genuine I was told not to skimp on it by using off brands. I'll see if I can get a pressure test done. I don't have many diagnostic tools so might take a bit to have it done. Further, cat is not glowing red so I know it's not totally plugged. I don't appear to have black smoke coming from exhaust at least while idle.