Loss of Power

[USCSOS]

I have a 1999 DSDP, Cummins 300 ISC. When climbing hills, it loses power, down to 35 mph when it used to be able to hold at 47 on same type of incline without a problem.

The air filter is fine. Fuel pump is relatively new.

The interesting fact is if I have it on cruise control, there is no power loss. Climbs hills with ease.

Can anyone tell me what may be the problem here?

Thanks in andvance for any help.

Stanley Smith
99 DSDP
Cummins 300

[USCSOS]

I have a 1999 DSDP, Cummins 300 ISC. When climbing hills, it loses power, down to 35 mph when it used to be able to hold at 47 on same type of incline without a problem.

The air filter is fine. Fuel pump is relatively new.

The interesting fact is if I have it on cruise control, there is no power loss. Climbs hills with ease.

Can anyone tell me what may be the problem here?

Thanks in andvance for any help.

Stanley Smith
99 DSDP
Cummins 300

["007"]

USCSOS Welcome to the Newmar forum and irv2.
Not sure on a DP but if there is a control off your foot pedel thats not sensing the shift points for the transmission as your CC is. Would think both would go to the same control.
Is the foot pedel free to act to your responses?
Someone should pick this up and I will send to Spartan chassis forum also.
Enjoy the forums and do post often.

[RV Wizard]

Stanley, welcome to iRV2.com. Glad to have you here. Look closely at the throttle to br sure you have full range of movement. Make sure you were not in the economy mode on the transmission by mistake nd retry the same grade if you can. Let us know what you find.