Update: front o2 sensor is reading .05v when warmed up, not fluctuating at all

I would boost leak test it you could blew a vacuum line off or intercooler pipe on the hard pull and that would explain a lean idle.

Well it actually turned out to be one of my o2 housing bolts fell out, causing a slight leak at the downpipe. Put new ss bolts with lock washers all around and we're good to go. Thanks for your reply!

So a few months down the road here, I've now got an lean idle issue. On a cold start my wideband will show a healthy 13.0-15.0 at idle but then once the o2 sensor stops cycling for the cold start, the a/f sinks and eventually goes below 22.4, only coming up when under load, when the car appears to be functioning appropriately. Come to a stop, however, and my wb reads 22.4 again until I get going.

I'm in the Lansing area in Michigan, and this started happening yesterday just as the weather got considerably colder. I'm sure that is just making the issues more apparent. One thing I did do was unplug the o2 to see if the car goes rich due to closed loop. While it does richen it up a little bit, the wb still reads around 17.8-18.0 at idle, dipping down into the 20's every so often. I'm going to try to visually inspect my ecu for bad caps and what not but I was hoping someone could offer me some other ideas as well.

Thanks guys.