I'm sitting in the car, waiting for a flatbed. My afr gauge just went wacky. Suddenly afs showed as super lean. No display. Car seemed to run fine. Shut it off and restart gets me 14.5 afr. After a few seconds they climb over 20. Shut it off for a minute and all back to normal. Drive a couple minutes and it spikes again. Do you think it's a bad wideband? I don't have my laptop with me.

 

Id start with seeing if there is a exhaust leak pre sensor.

 

Everytime I've had a wbo2 sensor fail it acts like that (reads super lean). So it could be as simple as a failed sensor. Make sure it's far enough from the downpipe/header, and is mounted off the side (not the bottom) of the pipe so it doesn't get moisture.

 

I'm inclined to think it's the sensor. I noticed, as I sit here, that idle afr is fine. If I slowly raise rpms, afrs spike. Fuel pump is maybe a year old. Before noticing it was lean, I took a couple hard pulls and everything ran fine. Now with engine off and key turned on, I'm getting afrs between 16 and 17.

 

I didn't have a chance to play with the car until today. I've run it through several fan cycles and drove for 15 minutes. No irregular afr readings. Could it be that the wideband got fouled, because I'm running pig rich. I don't want to start throwing parts on it wothout reason.