This will be a bit long, but I have no good ideas. Truck is 01 ETH w/EZ. Sat. morning after driving over washboard (bumpy) road about 1. 5 mi. to highway. Start up slight incline shifting normally, hit about 50 and no more acceleration capability. Push accelerator to wot and won't get above 50mph. Pull over to check engine, see nothing unusual, take off and all is normal for the rest of the day and Sunday. This morning same spot, i. e. going up incline on pavement shift normally to 65, then nothing more. Giving it more accelerator does nothing. Stays at 60-65 so I keep driving. About 4 miles down the road I feel a surge and truck runs normal again, i. e. can accelerate, etc. Both times fuel pressure stays normal, 13-15psi. EGT's stay steady and no boost increase. Only other constant is that Sat. a. m. and this morning were cool and damp. Seems like it is not getting fueling for some reason. Could it be the EZ? Any ideas would greatly be appreciated. By the way no codes set that I can tell. I do have a stored 1693 from last fall when 1st EZ went bad, but nothing new for codes.