Hey! That's ME!
Glad you're please with the tuner and hopefully, we can get you to where "dead" is at, .8% error on the MAF file (Ford is +/- 4%). I jokingly told him I wouldn't touch it again because it can only get worse..
The Data-Logging is quickly becoming my favorite feature of the XCal2's. I've been tweeking the Wife's SOHC Explorer for our NorCal trip next weekend and I had a 6% left/right bank error that suggested the passenger upstream O2 was bad. Got under it today (while doing Pro-Comp ES9000 shocks) and pulled both O2's. The EASY one (driver side) was a Bosch OEM replacement, the Passenger side took over 1.5hrs to remove (through the fender well! remember that trick!) and guess what? OEM Ford, 8 years old with 83,000 miles on it, the body was scraped/dinged and the corners rounded. Someone tried to remove it and failed. Coming from the fenderwell I got a good grip and it pulled right out.
New O2's and the error is undetectable. Gotta' love the data-logging. So far I've found unbalanced injectors, an exhaust leak and bad O2's on two vehicles.