Engine/Transmission (1994 - 1998) RPM Surges

[Stiger]

I have a 1994 3/4 ton 4x4,automatic transmisson,with 105,000 miles. I have experienced RPM surges (up for a few seconds then back down) in the past and now they are more frequent and last longer. I get about a 100 rpm spike and then it returns to normal when at constant rpm/speed above about 50 mph, a couple times a minute It does not matter whether I am in cruise control or not, or OD or not. I took it to the dealer and they did about $1000 + worth of work to the fuel system and it still acts up. Any direction I should look in? Thanks.

 

[Turbo Thom]

One of two things. Fuel supply are governor problems. Have you checked your governor spring in the pump? I don't now of an electrical situation that would cause that? The lift pump feeds the injection pump, so did they replace that? When you stop, does it idle and sit still ok? Wen you leave, how does it act?

 

[DBrickel]

Sounds like the TPS. (Throttle postioning sensor) Go to dodgeram.org click on tests & repairs then click on Tps.



that is a great site to learn about your truck

 

[Turbo Thom]

I missed the automatic. Sorry

 

[Willys]

Could be the brake light switch plunger out of adjustment. I had the TPS and that bad at the same time, it was a bear to track down(THANKS TDR MEMBERS!!!!!) because I was young and inexperienced... The switch still needs adjustments every so often.

 

[46mech]

Stiger,



In the 10 yrs I've had my truck I've experienced these symptoms on three different occasions. The first and second events, as I recall, the symptoms were remedied by: 1) replacement of the TPS 2) cleaning the TPS. Typically, I recall these times the symptoms were always at highway speeds.



This third time the symptoms seemed just a little different than before, and they started about a year ago. Things progressed to where it didn't seem to matter if I was towing or empty, keeping the OD off or on, at 70-65-50 or even at 40mph. At first, when these symptoms started popping up again they were so infrequent I thought I had a problem with the TPS again.



Long story cut short, my torque converter was slipping and now I have an awesome transmission by a local guy who has an understanding of power. I don't have those symptoms anymore. I don't know, drop your transmission pan and look at the filter and fluid. Does it look dirtier than it normally has? I change my own fluids and I knew over the course of about the last three or four transmission fluid changes that the fluid and filter were dirtier than usual.

 

[RDelissen]

1) replacement of the TPS 2) cleaning the TPS.

same on mine

Just try cleaning and tightening the TPS first, to see if that cures the problem ...

 

[DBrickel]

If you try cleaning the TPS use electrical contact cleaner not wd40.