sounds like backfire when auto shifts?

[crazy_camry]

for the past couple of months, my Gen 2 (3s-fe) has been sounding like a honda with an exhaust. i have a 2" catback with canon muffler, and it sounds like one of the baffles had broken inside, and it made this tinny, whiney sound above 2200rpm. today i cut off the muffler, and sounded fine till i hit 2200rpm, then made the loudest burbling, backfire noise, which then happens again at about 3700rpm. it seems to happen when the auto is shifting. the muffler was welded back on, and the noise (now muffled again), happens at exactly the same time (rpm wise). so now i think the muffler isnt broken, but something with the engine? it wasnt happening before, but is really annoying. what might be the problem? Thanks.

[SolaraTRD]

You have the all famous "Mis-fire system" as seen on "initial D" And the whining noise is due to the Turbo you have now that mysteriously installed itself over X-Mas by: SANTA

[crazy_camry]

dont know bout the misfire system, and the whining is weird, cause my turbo isnt even in yet

[Nico]

Problem with valves I would say ... ?

[crazy_camry]

i can hear a distinct 'valve tick' from the engine, though 88LE says not to worry about it. maybe engine is out of tune in some way?