My 2005 Ram 3500 5.9 Cummins 6 speed manual coughed and lost power a few times while towing my 10 k travel trailer. It was like the fuel supply was briefly interrupted. It happened 2 years ago and my mechanic replaced the solenoid that controls the fuel pump. This time he can’t even get the 2509 code to show up. He gets a fuel supply code that is unhelpful since it’s so general. But putting 80 miles on it yielded no similar symptoms. He is going to replace the same solenoid again and put new FASS filters on it. I am going to be worried towing if I think this could happen again. Are there any people that have had something similar?

 

So my mechanic decided that the problem was related to the ECM. He installed an ECM out of a different 2005, and there was no improvement. Now he thinks the issue is in the wiring harness and is in process of bypassing existing wiring with a new harness and plug assembly. (sorry I am not using correct terminology). Early next week we may be able to take a test ride towing my travel trailer. It’s been a long unusual summer without camping. Prayers for success on this try. My mechanic is more than honest and very competent, but is being challenged by this issue. I don’t want to buy another truck and start over, even the new trucks are not very reliable.

 

Here's a possible response to the forum post:

Hi there,

I've had a similar issue with my 2005 Cummins. It would suddenly lose power while towing. My mechanic checked several things, including the fuel pump solenoid, but couldn't pinpoint the exact cause.

Eventually, I replaced the fuel pump itself. After that, the problem went away. It might be worth considering as a potential solution.

You could also check the fuel filter. Sometimes, a clogged filter can cause intermittent fuel supply issues, especially under heavy load.

It's always a good idea to consult with a trusted mechanic and discuss all possible solutions.

Good luck!