Ever since I installed a wideband I've observed that my AFR goes full lean whenever I let off on the gas pedal and am under engine deceleration. All of a sudden starting yesterday, my AFR goes rich instead of lean on deceleration. I'll be cruising at 14.7AFR and when I let off it will hover around 12-13.5AFR. Any idea what's up here? Leaking injector? I checked my fuel pressure gauge about 5 minutes after shutting off the car and it was still holding pressure.

Also, I noticed the car has been running a bit rich during cruise, but this might be b/c I fixed some exhaust leaks recently. I didn't notice the deceleration issue 'till a few days after fixing the exhaust leaks, so not sure if they're related.

Thoughts?

DERP, I might have already figured out my problem. I was messing with throttle stop and TPS a while back and currently have the TPS mis-adjusted. I think it reads around 13% when I let off rather than the usual 10%. This is probably keeping the engine from cutting fuel during decel. I'll respond with results after I check it. Any thoughts on any other factors that might be causing this?

Sounds like a culprit. The ecu has a TPS threshhold before engaging DFCO.

Yup it was. TPS was reading 3% on Zeitronix (Zeitronix actually shows 0% like it should, not 10% like other loggers), so I adjusted it and *bam*, back to normal. Strange how I only noticed it yesterday. Last time I messed w/ the throttle stop was a few weeks ago. LOL serves me right for starting a thread before thinking about it for 30 seconds. Meh, maybe this info will help someone else out someday...

This happened to me once when I was replacing the fuel filter. I broke the wire to the closed throttle switch on the back of the throttle body. The ecu cuts fuel on decel at any rpm above 1200 I think it is, I'm sure you knew that already.