too rich codes

**LeadFarmer** · 02-02-2012, 09:20 AM

Lately I've been having problems passing inspection. Took it in and it's throwing codes for too rich on both banks. So I went in and changed the plugs(NGK TR5s), and wires, cleaned my K&N filter, and cleaned the MAF-which is stock. I had the computer reset, but 20 miles later the codes came back. What gives? I did the math and i'm getting 20mpg in the city with stop and go traffic, so it isn't pissing gas. When I took the plugs out they were pretty dark on the ends, but i've seen worse. I've used injector cleaners, seafoam, etc.

I do think it's worth mentioning that I may have a tiny vacuum hose leak somewhere, revs tend to play around .9-1.2k rpm when cruising in neutral, could that be it? Or is there something else i'm missing? Mods in the sig.

Oh and the car has no cats, but the rear O2s haven't been deleted, could this be causing it? I always thought the rear O2s had nothing to do with adjusting that sort of stuff but maybe i'm wrong?

**0rion** · 02-02-2012, 10:19 AM

Originally Posted by LeadFarmer

Lately I've been having problems passing inspection. Took it in and it's throwing codes for too rich on both banks. So I went in and changed the plugs(NGK TR5s), and wires, cleaned my K&N filter, and cleaned the MAF-which is stock. I had the computer reset, but 20 miles later the codes came back. What gives? I did the math and i'm getting 20mpg in the city with stop and go traffic, so it isn't pissing gas. When I took the plugs out they were pretty dark on the ends, but i've seen worse. I've used injector cleaners, seafoam, etc.

I do think it's worth mentioning that I may have a tiny vacuum hose leak somewhere, revs tend to play around .9-1.2k rpm when cruising in neutral, could that be it? Or is there something else i'm missing? Mods in the sig.

Oh and the car has no cats, but the rear O2s haven't been deleted, could this be causing it? I always thought the rear O2s had nothing to do with adjusting that sort of stuff but maybe i'm wrong?

answered your own question. Any exhaust leaks before the front O2's? How many miles are on your O2 sensors?

**LeadFarmer** · 02-02-2012, 10:36 AM

Originally Posted by 0rion

answered your own question. Any exhaust leaks before the front O2's? How many miles are on your O2 sensors?

I think they're stock, so 120k. i'm pretty sure there aren't any exhaust leaks. But I always thought a vacuum leak would cause a lean condition, so are you saying it's my lack of cats?

**0rion** · 02-02-2012, 11:38 AM

no not at all....vacuum leak *could* be causing it to over fuel but I agree that normally you'll see lean codes. That's a shit load of miles on those O2's.......even if they end up not being the problem I would swap those out. There's a good chance they're the culprit though if they've fouled and drifted.