I have been keeping up with the dreaded surge problem people have been having over the years because I thought if it happened to me I would at least have a starting point. Drove the truck all week with no problems, Hooked the 5th wheel up Saturday to go to Payson AZ. Truck felt real strong with box set on 3 sub 4. Figured the cooler weather really helped. Felt a little bucking (Like a head wind) every once in a while. Started getting into the mountain areas and the truck was lurching fore and aft real bad. Checked all the instrumentation and everything OK. Fuel press. at 9 EGT OK, what the he** is going on?. While changing settings on the box (more aggressive just amplified the problem) I get a 253 (open in injection pump detected) code check engine light. I get to the campground and check the pump tap and re crimp. Clean the ground. Drive solo back to Tempe with no problems. Problem only seems to appear with a good load on the truck at about 1/2 throttle on. I get off work today and start checking MAP, IAT and various other connections. This truck since new would stumble every once in a while for no rhyme or reason. I looked down to the injection pump to find the harness that is shown in the book and find there is a push/pull locking device to keep the plug in the pump and it is pulled all the way out
. Apparently it has been like this since new as no one has worked on the truck and I know I did not pull it. It took a little effort to lock back in and I am 99. 9% sure this was my intermittent stumble and real bad surge that occurred lately. It may be a good idea to check the plug on your pump even if you do not have these symptoms. I guess I will not know for sure until the end of the month when I pull the 5ver back down.
Dave

Dave