I have an 07 panel 2.4 auto 164k. Tc light has been coming on and hard shift to follow. Just pulled codes; po171, po010, po014, po054, po420, po455.
Recently installed cai, used factory piping from throttle body, past the mas. adapter to 3", to aftermarket filter. Also installed aftermarket muffler (free flow). I also recently installed both o2's (aftermarket, lesson learned). I've had evap codes since I owned it, ready to fix that too. Not too worried about throwing parts @ it, just want to get the right parts. Help?, direction?

 

P0420 means bad cat.
P0010 & P0014 mean bad wires or bad VVT valves
P0054 means a bad #2 O2 sensor heater (which could be the reason for P0420. Frequently caused by Bosch brand sensors or other cheap options.
P0455 is large EVAP leak. Check the gas cap seal first then the EVAP vent valve and its seals.

You have been driving around in open loop as long as there has been a CEL. That means that the computer has been working with guesses instead of feedback from sensors. That may have caused damage and less than optimum MPG.

 

I had o2 codes first, so I threw cheap o2s @ it. Won't do that again. Planning on oe o2s, vvt's, plugs, maybe mas, already replaced gas cap so I'll probably throw a vent valves & seals. It's my work car so I don't mind throwing extra parts at it.

 

Pop off the valve cover, is the timing chain nice and tight? Is the front timing chain guide intact?
the air filter is it oiled? Maybe too much oil?

 

My fav for O2 sensors is NGK/NTK. They make the OE.
Why even think MAS or MAF? If it ain't broke ....
The P0171 is probably from running open loop. Might be from the large EVAP leak.

 

The problem is obvious! That GMC Grille emblem!

 

The P0171 could be many problems, like cracked flex pipe dirty MAF , MAF not plugged in firmly.

 

Also look for corrosion perforating the evap line, lots of possible places mostly from mid-cabin all the way back to the tank. Caused mostly by clips and insulation blankets retaining corrosive brine when driven on salted roads. Same with the fuel line. Usually best to just replace them both.

 

I appreciate the info, so far I replaced both vvt's, that took care of the tc light. I had eom o2 sensors but the plugs were wrong so I sent them back. I have the evap parts so that's next. I feel like the Cai is causing some of the codes w O2s. I used the factory elbow past the mas, cut it off there and went to a 3in adapter right to an air filter. Mas seems ok, no codes on that, tap on it while running and it's fine. Maybe wiring to downstream o2, that's the only code that came back after vvts, and the evap code. I read some threads here a while back about how to check those wires, gotta find it. Either that or Cai is causing too much air flow and messing w o2s?? Hmm. I shall ponder this more.

 

If CAI means cold air intake to you; no that is not the cause of any codes. The cold air intake is the hose from the wheel well to the air filter.
Do you mean MAF when you write MAS? That is the sensor mounted in the rubber tube between the air filter and the throttle body. If the tube has cracks in it or the clamps are loose it might cause problems. What do you think tapping on it might test, beside damaging the heating coil.
What about the P0420? Have you checked Fuses #33 and #64 under hood? Have you looked at the exhaust flex pipe?