1999 dodge diesel engine surge

chrlin

!!! update!!! the dealer has had my truck for 2 wks. to date they have eliminated the TPS. they just changed the governor pressure sensor in the tranny. that has helped a little but has not cured the problem. the mechanic says that the torque converter clutches are engaging and disengaging. don't know if he is right or wrong but it still does it. factory reps do not seem to have been much help up to now. interestingly a 2001 dodge 2500 has just come in with the same exact problem????? they seem to think it may be the overdrive solenoids. don't know.
question??? I am in the habit of downshifting to descend a hill or to turn off overdrive, depending on the grade. is this harmful to the tranny and could it have a bearing on the problem I am seeing? also can the cruise control( on or off ) have any bearing on the problem?
do I need to be adding cetane/boost and biocide to my fuel? saw a discussion involving other vehicles but not the dodge. the dealer does not favor it one way or the other.

Mr_Shiftright

I can't tell from your post if you are getting a "surge" (increase in actual SPEED with steady throttle pressure) or an "unauthorized downshift", or increase in RPMs but not speed.

Two different problems. Sounds like the dealer is hunting for a shift problem, not a real surge problem.

Downshifting to brake down a grade shouldn't harm anything, and cetane booster/fuel conditioner and a biocide are always a good idea on a diesel. What happens is (weirdly enough) that diesel fuel can grow algae, for one thing, and can also congeal in cold weather.

chrlin

thanks for the info on fuel. to be honest i can't tell if it is an engine surge or an unauthorized shift. the dealer is guessing at this point. i will update as things go along.