The guy with the Suburban was actually sent by my insurance company through my roadside assistance coverage.

So, a week ago I was at Wally World and bought 2 bottles of "Diesel Kleen" - one was labelled as being specifically for winter fuel treatment and the other more of a "cetane booster." I put the "cetane booster in my tank yesterday morning at the beginning of our trip, I'm guessing that was the wrong one to use!