Strange problem - Any Suggestions

[ACoyle]

1) 99 Quad Cab 4. 10 auto.

2) Truck has been running fine for some time - No mods in the last six months.

3) Weather - Spring like 40 - 55 temps. Humid.

4) Starting, Idling and acceleration are all OK.

5) Driving along steady at highway speeds (50 - 70) the rpm will fluctuate 100 rpm intermitently. Seems like TC locking and unlocking.

6) Asked Bill K. he suggested TSP 18-02-99 (reflash of software).

7) Changed fuel filter, no immediate effect.

8) Temp warmed up to 70 - 80 Problem gone.

9) Don't mind doing the reflash, just perplexed now that it is gone.

10) Anybody else seen this?

 

[KatDiesel]

I assume transmission fluid level is fine, and the condition of it?

 

[ACoyle]

transmission Fluid has 20K on it. Looks like the day that It went in. I probably will have it serviced pre-Summer. The problem got surprizing when it went away.

 

[BFC]

Mine did the same thing. Jumped in and out of lock up, then on Monday I changed the oil/filter, the fuel filter and put in a new fan clutch. It quit doing it. That was until this afternoon, it started jumpin' in & out of lock up again. Guess I'm goin to the stealer monday. !



Glenn

 

[MidwestMotorman]

IAT sensor???

Could it be the IAT sensor? They usually cause problems related to temperature. Maybe it is making the computer think the truck is cold/warm, and is causing the TC lockup to be erratic?

 

[Big_Daddy_T]

Me too

I had the problem real irradict. Now its been gone for awile. My local stealers dont have much for diesel techs. So I avoid them like the plague.

Speaking of which I just had cummins northwest dial in my valves.

 

[ACoyle]

nathanbush - I am thinking along these lines as well. I don't think it would hurt to pull and clean the IAT and MAP sensors. I seem to recall that there was a big issue with them during the MAD ECM devemopement. I forget which sensor. When in doube clean them all.



Big_Daddy_T - I would rather not take my truck to dodge if I can help it.