2018 6.7 Cummins surging

[Ram6169]

I have just recently purchased my first diesel truck 6 weeks ago, 2018 6.7 Cummins. Truck has 80k miles and engine is still stock. Over the last few weeks I have noticed the truck surge a little bit when in reverse, idle and at cruising speeds. its random and doesn't happen all the time. Truck is not throwing any codes nor is any lights on the dash. I've read multiple things from bad injectors to fuel pumps to bad diesel. I do have extended warranty from the dealership. Any thoughts or advice is greatly appreciated.

 

[chri5k]

Make sure the fuel / water separator is empty. It is under the truck just ahead of the spare tire.

 

[18CrewDually]

Being the truck is "new to you" I'd start with fresh fuel filters MOPAR or Fleetgaurd only. Dont cheap out. Buy from a reputable company. I've now personally dealt with 2 Chinese Mopar knockoffs that created problems .
Like said above, primary is under the truck attached to the chassis almost directly above the rear axle & driveshaft. It is a spin on with a water sensor in the bottom that gets reused. There is a special wrench for it but if it's not too tight you can use other tools. They are O-ring sealed so you do not have to overtighten them.
The secondary is on the driverside (left) of the engine on the side of the block. It is a canister style. Again don't overtighten the plastic lid.
Anything more than that I'd want to hook a good scanner to it that can read sensor parameters to see what fuel rail pressure is doing.

 

[Ram6169]

Ya I have an appointment Monday at the dealership, I’m gunna have them start there with the fuel filters as I have 2 free services. Hopefully that’s all it is, when I checked the water/fuel it was dirty as in looked like it hadn’t been changed in a while. The fuel was good tho, got some in a jar and no water inside.

 

[smiley]

Ya I have an appointment Monday at the dealership, I’m gunna have them start there with the fuel filters as I have 2 free services. Hopefully that’s all it is, when I checked the water/fuel it was dirty as in looked like it hadn’t been changed in a while. The fuel was good tho, got some in a jar and no water inside.

Did that fix it?

 

[truck2569]

I have just recently purchased my first diesel truck 6 weeks ago, 2018 6.7 Cummins. Truck has 80k miles and engine is still stock. Over the last few weeks I have noticed the truck surge a little bit when in reverse, idle and at cruising speeds. its random and doesn't happen all the time. Truck is not throwing any codes nor is any lights on the dash. I've read multiple things from bad injectors to fuel pumps to bad diesel. I do have extended warranty from the dealership. Any thoughts or advice is greatly appreciated.

When was the last time you changed your fuel filters. Is it the first half of 18 the truck was made or the 2nd half of that year. Do you know which High Pressure pump you have in your truck is it a CP4 or a CP3. The CP4's have recall on them.

 

[18CrewDually]

When was the last time you changed your fuel filters. Is it the first half of 18 the truck was made or the 2nd half of that year. Do you know which High Pressure pump you have in your truck is it a CP4 or a CP3. The CP4's have recall on them.

Only 2019 & 2020 MY came with CP4.2. OP has an 2018, CP3.