I have a 2003 5.9L 4x4 Ram that has very little power off the start. Once I get to around 15m.p.h. it takes off like nothings wrong. If I'm at a dead stop and mash the throttle in gravel it won't spin the tires until i get to around 15mph or so, and even when it shifts to the next gear if my speed isn't up and the rpm drops to low on the next gear it looses power. If I pull up to my car ramps and once again mash the throttle just to climb the 12 inch ramp it struggles. I'm not sure if its a torque converter issue or if its due to the cat or fuel filter. I'm at a loss. Anyone have any idea's?

 

My 2000 Ram Cummins does the exact same thing. Its got a 5 speed in it. Did you ever find out what was causing it. It's driving me nuts because I do a lot of towing.

 

I would think if it was a fuel/air problem it would be also stumbling, or wanting to die. However at the same time it could make sense that lack of fuel/air pressure could cause this. I am speaking in general mechanics from working on cars for years, i am still learning the hemi as i go since i just bought one about 6 months back!

 

This is a really old thread, and not enough info is given..

If the 5.9 is a gasser, and there were a handful in '03, it would be a 46rfe behind it.. those things are notorious for dropping gov transducers and speed sensors, which most often disallow a first gear drop.. meaning the truck starts in second gear.. which would seem like it has no ***** off the line, because it doesn't..

To check, drop the manual shifted to first and see if it works..

The dude with the manual, I don't got anything for ya.. sorry..

 

Yes greenmachine64 I did find the problem. My truck was a gasser. I sold it and 2 weeks after selling it I was called by the buyer and the torque converter blew up in it. So it must have just been on the verge of going out when i had it.