Well when I was driving it, I noticed when it backfired, it was through the exhaust. From the rear view mirror, it blew all the dirt off the road like a big fart and I actually could see the dust plume and it was loud. It also just occured to me that since I've moved, I cant borrow some of the tools I used to use like a fuel pressure gage, jacks, and others stuff. I do have a multimeter and vacuum pump/gage so I can check out that stuff. I can check for fuel but not pressure. Anyways theres two important symptoms.
First when in normally aspirated mode it behaves like its got a vacuum leak or low fuel pressure or it just runs fine.
Second when the supercharger kicks in, it either roars and you can hear the increase charge or flow go in or it fails and there is no roar and it backfires like a grenade. Engine also cuts out however supercharger light stays on. I guess no roar means no supercharging leaving a rich charge and then bang! The excess fuel goes off from the exhaust.
Anyways when this problem manifested itself, all was well then after the initial bang the engine has not run well since. something could have broken then.
