I use thinkcar's thinkdiag along with my phone. It's ok, but I wouldn't be surprised if there are better scanners for the price. To give you one additional data point - when my engine is cold I do have STFT varying ± 5% with no issues.
I don't think what kong has would be enough for detonation. Usually pinging doesn't start until about +10% on STFT. I had 12% or so STFT when the car pinged. (Of couse my car would ping worse in Winter since more unmetered air would enter the system.) Check engine light (which is designed to...
Only with PP2. Notice that the part that caused the vacuum leak is part of PP2. Now both my short and long fuel trims are close to 0 at all RPMs and I get no pinging whatsoever.
Yep, I had pinging at low RPM due to a vacuum leak on the hose that attaches at 90º to the intake piping past the sensor. Some plastic weld fixed the issue. Easiest way to tell that you have a vacuum leak is to look at live OBD2 data for short term fuel trim on both banks using an OBD2 scanner...
See page 3 of the instructions booklet. It plugs the hole left by the sound tube in your firewall. The filter housing gets its air from the front of the car via the slot and the small hole on the bottom is the drain hole for water entering it.