I have a 2007 Yukon Denali XL with 27,500 miles on it. My wife and I just got back from a 600 mile weekend road trip and on the way home I noticed the truck surging/jerking every now and then when I was going around 75-80mph. It almost felt like the compressor kicking on and off but very harsh. It felt like it was coming from the transmission area. Didnt feel like an engine misfire but I'm kinda at a loss. I would appreciate some thoughts. Thank you.