I need some help. I run a 2001 3500 2w drive dually 5 sp pulling a 40 gn trailer. Starting friday afternoon, my truck would get sudden power loses, usually in 5th gear. It will surge several times then resume operating normally. I might drive several hundred miles then out of the blue it will start surging again. I depress the clutch to see if it dies but it just goes to idle. When it's running right there is no problem, no lose of power and no misses.  This is what I have done to it since march, I've put in a new lift pump, we have some wiring issues to the lift pump which was corrected and the block pump is completely out of the picture. The lift pump is an in tank model. I checked the lift pump on Saturday and it's putting out 15psi at idle and 13psi at 2000rpm. The only code I get is a 1593 but when I put my odbII reader on it it shows no codes. I have replaced the TPS couple of months ago, I got new bosch 40 horse injectors with new fuel tubes. I would say that there may be a short in the electrical to the pump but it would die  when I clutched it but it doesn't just goes to idle with no misses, normal rpm. I am wondering if the lift pump is going bad and is slowing down causing the pressure to drop, the engine can idle on lower fuel pressure but not run higher.

 

I'm at a lose, any suggestions would be greatly appreciated.

Saturday and it's putting out 15psi at idle and 13psi at 2000rpm

 

Is this highway RPM or neutral RPM?

 

The only code I get is a 1593

 

Typo?

 

 

I'm at a lose, any suggestions would be greatly appreciated.

 

Do a AC noise voltage check on the alternator.

Nope no type, and the fuel pressure is in neutral in the garage.

Nope, your right it was a typo, the code is a 1596.

Is this highway RPM or neutral RPM?

 

 

Typo?

 

 

Do a AC noise voltage check on the alternator.

Yes, it was sorry, 1596. The pump pressuse is sitting in the garage not whi

Yes, it was sorry, 1596. The pump pressuse is sitting in the garage not whi

No while pulling a load.

I need to see load pressure. Free revving is typically very very low volume requirement. (0.1 GPH maybe) But under full load powering down the highway the flow rate is way different. (~20 GPH) This why you should always have a pressure gauge in the cab.

I need to see load pressure. Free revving is typically very very low volume requirement. (0.1 GPH maybe) But under full load powering down the highway the flow rate is way different. (~20 GPH) This why you should always have a pressure gauge in the cab.

Thanks

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/59-obdii-error-codes/222-p1596-speed-control-switch-always-high

 

Ed

Thanks for everyones help, unfortunately, we all had it wrong. It wound up being the injection pump!!! 1400.00 bucks later and it's purring like a cummins.

1400...... Where did you buy it?? Much cheaper vendors out there with the same quality product