Ok so I have a bit of car problem right now. Pontiac g6 2009 4 cylinder. Ive replaced the battery, gas cap twice, 02 sensors front and back, new air filter, and even took it to a mechanic and they couldnt find a problem so they cleaned some sensors off (not sure which ones). I checked fuses and none showed signs of damage, and lightly sanded off some ground wires for better connection. Awhile back started getting a check engine light which was P0171 (Bank 1 system too lean) so I changed the 02 sensors and didnt work. I then started to get an engine power reduced. I would turn the key but not start the engine up and it would give me that message, I would take the key out a few times and the message would go away and car will start up just fine. Fast forward a month and engine reduced wont go away, if it catches its very heavy. And when I turn the key, I hear some sort of buzzing noise for about 2 seconds around the EBCM. I took the Throttle body out just before that issue started and cleaned it because it was really dirt, there is some gunk still on it that wont come off but I do not want to damage it by chiseling at it, but still giving me that error. Any ideas?