2006 Colorado w/ K&N intake and Flowmaster exhaust. 61,000 miles as of 05/2012. Bought the truck new and drove it like a baby for the first 25,000 miles.
At about 38,000 miles I floored the accelerator and at about 40 mph the truck went into "REDUCED POWER" mode. Pulled over, restarted the truck a few times until it began to run smoothly, but the check engine light stayed on until the next day. The problem disappeared and returned the same way about 10-15 times over the last few years, but restart it and it's fine for a few months or so.
Took it to the dealership on the third time and they found no problems, just codes and said to bring it in when the code is thrown again. I don't have a lot of free time to drive to the dealership, so I started researching online and cleaned the MAF sensor and the air filter. Worked fine for a few thousand miles and the problem returned.
Found this forum, bought a OBDII scanner and got a p0068 code. Took apart the entire air filter kit and cleaned everything (filter, tube, hoses, and MAF sensor) and for the first time cleaned the intake manifold on top of the engine (lots of carbon build up) Re-ran the scanner and no codes. Drove the truck really hard for about 20 minutes trying to throw the code and no problems so far.
If anyone has had any solution to this problem other than cleaning the intake assembly and MAF or replacing the PCM please help out. I'd like to keep the truck since it's paid off and has really low miles, but I'm ready to unload this truck for something new if it doesn't work after all all this.