I usually park my truck in the garage, and when I start it up I drive away or pull it into the driveway. Yesterday I was going to work, and it stayed in the driveway the previous night. I decided to start it, let it warm up. I never touched the throttle at all, and after a couple minutes of idling properly it was as if someone turned off the ignition switch. It just stopped running, no stumbling at all. Well reduced engine power was on my display, and it would crank but not start. I drove my 99 to work. When I was done, I hooked up a scanner, and got P0068 2 times, and P0106. I unplugged the MAP, and plugged it back in thinking there may have been some corrosion on the plug. I also did this with the T-body, original plug, and X-link. I started it up again, same thing after a couple minutes(i hadn't touched the throttle at all this time either), and the same codes. I cleared them, started it again, and rev'd it up a little. It ran fine, no codes. I drove it to the track and work today, and it has been fine. It appears that I get this if I don't touch the throttle at all. Anyone have any ideas?

 

An 18" section of harness from the throttle body seems to get moisture/corrosion inside the wiring and cause sporadic signals. My former truck (2005 Suburban) had that harness replaced for the same problem which fixed it.

 

Thank you, I will take a look at that.

 

Also, coincidentally, the problem started when I left the hood parked outside the edge of the garage and rain dripped on it.