My 1999 yukon has been running very rough lately, not wanting to start, and wanting to die when I can get it to run sometimes. It also almost seems like the engine and exhaust are what can best be described as chugging. I unplugged the MAF sensor while it was running and it didn't shut off or give me a check engine light and possibly ran a little better. I was originally under the impression that I may have had a bad head gasket, but when I went to rent a compression gauge I was told I may want to check my MAF first. So I'm unsure of where to go from here.