hiltsy855

iTrader: (35)

'02 Camaro, specs in my sig. I did my own tune a couple years a go with EFI Live and I was pretty happy with the results. I have an LC1 wideband with a display so I can see A/F ratio. It didn't always lock in at 14.6 but would maybe vary a few tenths up / down, no biggie. But out of the blue last week it started going real lean on cruise, idle, everything, and it jumps all over the place - maybe 14.0 all the way to 17 - averaging 15.5 or so. I re-calibrated the LC1, still the same on the display and verified by EFI Live. I don't get a check engine light and I can't find a vacuum leak. LTFTs are +10% or so which verifies the lean condition. WOT seems good and the A/F goes to 12.2. and stays there. Can you guys suggest some things to check? Do I have a bad O2 sensor? Thanks in advance.

SSpdDmon

iTrader: (10)

Could be a vacuum leak, exhaust leak, bad sensors, dirty MAF, or maybe a coilpack that's on its way out.

jimmyblue

iTrader: (11)

A misfire can also jack the exhaust oxygen content, and
the fuel trims that follow it. Might see if you've got anything
showing there.

hiltsy855

iTrader: (35)

Ok, I'll do some more checking. I know I don't have any exhaust leaks, not audible ones anyway. And wouldn't a misfire make it go rich not lean?

Old Geezer

iTrader: (3)

Fuel psi is?

hiltsy855

iTrader: (35)

Good point. I don't have a gage installed, I probably should get one. The odd thing is I get 12.2 as commanded at WOT.

Mike@Diablosport

iTrader: (2)

commanded will always show what your tune is commanding, if you're AFR used to match the commanded AFR, and noes not any longer, then something on the car has changed...

joecar

Do you have any recent logs of the problem showing the pids HO2S11 and HO2S21...?

hiltsy855

iTrader: (35)

Just an update - I replaced the wideband & O2 sensors and everything's cool now. Thanks.