EGR solenoid has been replaced by dealer, vacuum leak corrected at EGR. Vaccuum tests of EGR valve show valve o.k. No other codes generated after above repairs/systems check. 50 miles into the trip today, problem recurs, only when engine hot/under load. Coil replaced, wires and plugs replaced. Fuel pump problem ruled out by switching between tanks to verify pump operation--unless both pumps are simultaneously bad, can't imagine that it is a fuel problem. Truck engine totally rebuilt at 140K miles, as well as transmission replaced at that time, both done by reputable independent auto repair shop. Now has 150K miles, and this problem has just surfaced within last few days only 300 miles into a 1100 mile trip with 5th wheel. Any ideas/suggestions/tips?

 

You're in the wrong forum for the 7.5 engine.

 

Make sure #7 and # 8 spark plug wires do not run next to each other. If they are routed next to each other voltage will induce in the other wire at the wrong time and will cause a miss.