Sorry if this is a repeat, Looked through 30 pages. No search.

I use my 2004 F350 6.0L dually only to tow. It had 33,500 flawless miles towing. All stock. On one of my off months of racing, I decided to bring my F350 to the dealer for the first time to get the mandatory 05S34 recall. While at the dealer, I was informed I needed 2 other recalls performed. The work took 4 days. The 05S34 recall took 2 days itself. My wire harness had no chafing, but was replaced.
The truck ran alittle different (in tow mode), but worked great on two 70 mile trips. On my first long trip this last weekend, the truck bucked a few times and flashed a few lites on the dash. After the 6th buck, the engine dummy lite came on. I made it to my distination okay.
I noticed the bucking occurred only after I had pressed the brake pedal. While leaving a restraunt (no trailer) the truck bucked, and the engine died. After 10 minutes I was able to start the engine, but found I could only press the throttle 25% before it would buck and die. This seemed to allow only 1500rpm. I found out later, the 6.0L is a fly by wire, no mechanical connection to the engine.
After a day of racing with my daughter in Jr Drags, I attempted to drive home with the trailer. I only made it 5 miles. I managed to get the truck back to the dealer, eventually towed. The fault code indicated the wire harness the dealer changed went bad. The dealer found no chafing, but the harness went bad. Bad installation or defective part?
I should have followed others advice on FTE. If it aint broke, don't fix it.
I used my 1998 F250 (2001 4r100 trans, ATI supercharged), to retrieve my 34 foot Weekend Warrior Trailer bumper pull. I was amazed I could tow this 13,000+ lbs. trailer with a truck rated for 8,000 lbs. It's nice to know I have a backup.
Jay