just popping when the throttle is closed.. no loud 'bang' etc. it's very odd; it seems to be most prevelant under de-cel load downshifting from 4th to 3rd. Odd. I'm sure its no big deal mechanically/damage, but it's just slightly annoying. maybe it's my downshifting habits from the sport bike - which the gears were so close to one another that downshifting was frequent to keep it in the meat of the power band. I'm not sure if the ECM employs any type of Direct Fuel Cut Off under vacuum like a lot of FI cars.
I thought it might be running lean or an exhaust or intake leak. but..
I installed XiEDs to bypass the O2 sensors; and I don't think it's an exhaust or intake leak since I didn't mess with the throttle body itself (only the a/c) and the position of the 02 sensors.
The XiEDs seem to do the trick to throw a little more fuel in there up to about 40-50% throttle - which is about 90% of my riding anyway. I'm also not throwing any codes from the Idle Air Control. And, i do have a little bit of carbon build up on the tips of the exhaust. so, I'm sure if anything, it 'might' be running rich - which is good rather than Lean Is Mean lol.
Thinking of maybe doing a W/O throttle run on a street near my house and shutting off the bike/coasting back to my house to check the plugs.
it's also very odd, as I've been running the current set up (slip-ons and a/c) for a few months and it just now started doing it. I also though it might be due to the lower air-temps, but i've been riding in cold weather since about February.
