butchie&michy

We bought the car 2 weeks ago and the other day the SES light came one. Originally I just assumed the last time I got gas the cap wasnt put back on tightly but when I pulled the codes it came up with Fuel Trim System Lean Bank 1 & 2. Anyone seen this before and have any idea what could be causing these codes. Other then exhaust work and a gutted air box w/ K&n filter theres nothing else done to the car that I can see but of course I havent had alot of time to really investigate the car.
Thanks

slow

iTrader: (7)

my guess would be the K&N got too much oil on the maf sensor.

Ryan

DrkPhx

iTrader: (15)

I stay away from K&N filters because of the oil and how it affects the MAF; especially on a "side feeder" vehicle where the MAF is very close to the filter itself. Clean it to make sure. A couple of years ago, GM also issued a notice about the same exact problem.

In your case I would say it's the gutted air box allowing more air in and it needs to be tuned. I removed the air silencer in the air box on my TB SS and the fuel trims went very lean (+12-20%), so I added fuel and now they're back to normal. Is the MAF screen still in place?

butchie&michy

Yea the MAF is still in place, I'll clean the MAF and see what happens, Ive seen it before when the filter is over oiled that it messes with a MAF. Is rubbing alcohol safe for these maf sensors? I just want to pinpoint the problem so I can correct it now so I do not run into a major problem on the road one day.