General [Resolved] Lean Idle and misfire?

[jasteel13]

Alright I just began having this problem I have done some trouble shooting and can't come up with anything else.

First off I have an S-AFC, Wideband, and a 1g motor in a 2g. The other day I was driving and it was driving fine and then I noticed at an idle my air/fuel starting going really lean like 19.0 20.0 and I was getting a lean misfire pop, so I used my S-AFC and just pushed the settings from like -10 to +25 just to get it back to 14.5 area. that worked for then but that also made my car idle at about 20 vac. When it idles normal (800-1000 rpm) it is about 12 vac but it also pops and is running lean. I have tried a new MAF meter and a MAP sensor, Also have tried unplugging the S-AFC and checking for vacuum leaks can't come up with anything. any help would be appreciated.

 

[ADrewzki]

...but it also pops and is running lean.

The pop that you refer to. Is it misfiring? A misfire is when you're running rich. You can't run rich and run lean at the same time. That doesn't make much sense.

 

[jasteel13]

well it only misses(pops) when the wideband is reading about 16.5 and up until i bring the afc settings to about +50 just to get it back to to 14.5ish

 

[twenty5psi]

Bad o2 sensor maybe?..But then again,I'd think that you would run to rich at idle with a bad o2 sensor because the o2 sensor would be reading lean all the time (no volts) and the ecu would dump a heap load of fuel to compensate..Also,Have you had this problem for awhile?..When did you do the motor swap?..Has this been since the motor swap?..

 

[jasteel13]

well i found the problem... bottom of cyl 1 intake mani gasket was blown out, i couldnt hear it because the motor was idling at like 1500+ . so i finally found that and it alright "for now" !

thanks for the help