Here's the fun I've been having with my 99 Yukon SLE. Last friday, I drove from work, to the golf course, played, got back in the truck, and, it was in limp mode. The tach, speedometer, and gear display didn't work. Had it hauled to the mechanic and it was diagnosed with a bad ignition switch. It was replace on Monday. I picked up the vehicle and drove it Monday night and Wednesday morning. Wednesday afternoon, it wouldn't start. No codes, no nothing. It turns over for about a split second and then dies. On Thursday, a buddy of mine brought over a $3000 code reader and scanned the whole thing. No issues. He then tried to start it for giggles. The SOB started!!! Started throughout the day and got me home from work. Went out last night to go up the street to the grocery and, you guessed it, it wouldn't start. Having the same problem today. I'm at my wits end here. Any guesses, tests, or hail mary's any of you have will be greatly appreciated! Have a great weekend!