A/F jumping at idle

[cwylie]

Im having an issue with my A/F jumping all over the place at idle. I though it could be an exhaust leak but I am not seeing anything. Could it be a had injector and when this cyl fires it causes a lean spike?

[David Pozzi]

Or a spark plug misfire. It can happen at idle with a lean mixture. Look at your TPS signal stability at idle. If TPS varies, the ECM will react as if the throttle is being opened quickly & add acceleration enrichment.