My work truck on this deployment is a 96 K3500 with a 6.5 turbo deisel. I've been driving it for about 8 months with no problems but the whole time the SES light has been on, but I don't have a scanner to see what it's for. All of a sudden a few weeks ago I was driving and let off the throttle and it went to WOT all by itself, bounce off the rev limiter and turned itself off. Now it's started to do it more and more often. I've never seen this problem with any other truck. Where should I start looking for what's going on with it?