Cummins hates rain
 

Anyone have an issue when it rains??? My truck for about 1 month now runs Horrible only when it rains!? I have checked grounds on the batteries but I am wondering if I am getting a short @ TPS or something worse?? PLEASE HELP:dang:

Explain in greater detail what your truck is doing.

OK it started to rain this AM after a long dry spell...It will fall off idle under 30MPH and try to die. It will lose power during regular driving conditions and then surge with small changes to throttle position with sometimes puffs of black smoke...then run like a scalded dog. Then at idle it sounds like it is overfueling and run with a real hard lope. When it initially happened we managed to get it on the laptop and it showed rail pressures that were VERY high during the overfueling at idle..replaced the overflow/overfuel valve and the problem persisted but it went away when it got dry out. When it happens it will throw all sorts of codes to included water in fuel and MAF sensor

id gather codes and see what the common circuit/circuits are that are causing the codes to set. like if it set maf and wif look on a wiring diagram and see if those circuits are sharing a ground or power. sounds like water is getting in somewhere in either the harness or a connector.

Did you look at the FCA? It controls the rail pressure...