Hi everyone. I have an issue hopefully someone from here can help me with. I have a 2007 GMC envoy with a 4.2L6 engine. I'll try to make this short but informative as possible. Over the last 2 months or so my envoy has been losing power little by little. It would be driving great with full power when all of a sudden I would hit a small hill and i can feel it lose power barely making it up the smallest of inclines. Also, it started to idle a little rough dropping in rpm's. So I decided to change the plugs with acdelco iridium's and take the throttle body off and clean it properly. That helped tremendously for a while. Then the same loss of power and idle jumping came back with vengeance. It also started stalling out when I took my foot off the accelerator. (Stopping at a red light). It will always start right back up and go. So I decided to check the fuel pressure and it was good. 55+ at the rail. Checked my coils and cleaned the maf sensor. It seemed to help with the idle issue because it idles great now. It just dont have any power. It kinda feels like it's not able to breath and the longer I drive it the worse it gets. If I really accelerate hard the reduce engine power light comes on and I have no pedal. I have to pull over shut it off, remove the key and wait 3 minutes, starts right back up and goes but with only about 30% of power. I have to baby the fuel pedal or the reduced engine power kicks in and shuts me down. I'm showing 4 codes with the most recent scan p0506,p0101,p0068 and p0411. A mechanic said it could be my throttle body itself so I spent the 300 bucks to get a new one and installed it myself. I did the "relearn" and it idles very smooth at 600rpm, but still no power when accelerating. The trans shifts fine. It starts and cranks fine. The thing I "think" I need to try next is maybe the catalytic converter. I just dont want this thing to nickle and dime me to death. Please help.