This is now happening on the highway, and I've run premium gas to eliminate the bad/low-octane gas variable. At highway speeds, if I gently put pressure on the accelerator, I hear a loud clatter/knock for a second or two. I have NO CEL, and no codes on OBDII.
Took it in, dealer said the clunk was normal engine noise from a boxer engine and that I was shifting wrong. They 'taught' me to rev up the engine before a shift, and slip the clutch. I can smell burning clutch and am not happy with their explanation to cause damage to the car intentionally.
Two scenarios:
-Low rpm shifting: at 2000rpm, I almost let off the gas just as I get on the clutch, shift and blip the throttle as I let out on the clutch in a nonlinear fashion (fast at first, slow at the engagement point). Nice, perfectly smooth shift, and knocking.
-High rpm shifting: at 3000-3500rpm, I do the same as previously, but wait for the rpms to drop (the throttle seems to hold at high rpms for a second before dropping), then shift. Again, smooth and more knocking.
Add to that the dealer way. Shift between 2500-3000rpm. Rev the engine when I push the clutch in, and slip it until I engage the clutch in gear. Sorry, this is NOT the way AWD shifting should work. The explanation has been similar to turning up the radio to drone X noise in my car.
What's going on here, and shouldn't the car register a code?
Edit: I checked all the body pieces around the engine, exhaust heat shields, etc, and all is nice and tight, no metal on metal.