I've posted this before but I'll ask again. Two of us have 2001.5 ho trucks with the same problem. Mine has about 97000 miles and other truck has about 54000 miles on them. Both have a random stumble. Other truck was taken to the dealer and new vp, lift pump, and not sure what else. Didn't help. Dealer said it was probably in the wiring harness and that was out of warrenty.I took mine to the bosch dealer, rebuilder and he put it on the computer and we took it down the road, got it to stumble a few times and it showed nothing on the computer, no censor problems or nothing.This **** is getting old. Got a good truck no one can fix. Can't up horsepower till I get it fixed, tst box just exagerates problem it has. Can anyone help!