Speed Control Linkage problems of the 1998 Chevrolet K3500

The problem I am contacting you about is unintended acceleration after selecting reverse. I brought this vehicle in to my selling dealer 13 times for this problem. Gm was apparently aware of this issue and called it an "idle flare-up". When this vehicle had it's "idle flare-up" it would suddenly surge backwards 6 inches to 6 feet, depending on the severity of the "flare-up" and how quickly I could get the vehicle stopped. Sometimes it wouldn't do it for several weeks, then it would do it 5 or 6 times in one day. Gm engineering had the dealer perform 3 different transmission repairs to attempt and correct this problem. A gm engineer even came out and drove the truck once, could not duplicate the concern, (hence the term "intermittent"), and then declined to recommend a buyback or trade assist. It was suggested that perhaps I was making this up to get rid of the truck. I am a landscape contractor, during my busiest time of year, wasting time and energy on this matter. Furthermore , it has cost me thousands of dollars to get rid of this chevy and purchase a new Ford. Gm has a problem that they are aware of with their 6. 5 powertrain and refuses to address it. Go get 'im.