I was driving down the interstate today and noticed that my Check Engine light came on and my boost guage wasn't registering. I turned off the cruise and pressed down on the pedal and the light went off and my boost came back. My Yukon has 260k on it and i haven't had it very long. But it didn't start doing this untill I had it up to 100mph and about 1000deg. Since then, it keeps doing this. Anybody have any ideas?