Hello all, I'm new to the forum, as well as Cummins and diesels in general. I've been reading up for a few weeks now, and I'm ready to post a question, as I have not been able to find anything that sounds quite like my problem.

First off, 2001 2500 4 in lift with 35's, intake and a super chip; all done by previous owner, and I am working my way through the issues he left me, as it's starting to become clear he drove it hard and put it away wet.

Anyway, I've read extensively about the fuel issues in this truck and I'm trying to nail down what may be the problem, if anything. I noted fairly quickly that I was not getting enough fuel pressure (around 5 psi and less w/ a hard load) and replaced the fuel filter. Solved the PSI problem (idles at ~13, never drops below 10 under load). It did not solve the buck at around 2000 RPM, however. I pulled the codes with the tuner and got the P0216. I have since cleared it and ran the truck in all configurations the super chip offers, and I get the buck and the p0216 in all settings EXCEPT when returned to stock. I absolutely hammered it in the stock setting and could not get the code to return in stock condition, but in every other one I do, including "hi-performance" which I find odd, as I would think I could get after it a bit more in this setting. (please correct me if I'm wrong in this assumption.) During all test drives the PSI never drops below 10, and I almost always get the buck at about 45mph, with the RPM at about 1900-2000.

So, finally to my question. Is this a symptom of a lift pump, an injection pump, my transmission, or is the chip not allowing me over 2000RPM? I've Troubleshot the Lift pump via bluechipdiesel's run down, and deemed the lift pump worthy, if only for the time being.

Any and all help with this is greatly appreciated. thank you!

 

Does the engine go past 2000 rpm? If so does the "bucking" get worse?

 

Yes it will go past 2000 RPM and no it doesn't seem to get worse. I described it as bucking because it was a term used in another trouble shooting guide and it seemed a good way to describe it, but its as though I lose power for a split second, just enough to drop the RPM's and either shift gear, or I back off on the throttle. It usually does it once and then it will shift into a lower gear. If I bring it back up in to that RPM range it will do it again. I've done it with a friend in the truck and he described it as a cylinder being shut off/or is bad.

 

Post this up in performance and accessories, or search in there. I think you'll get more hits...

Sounds like it is stumbling for fuel, or the APPS is acting up with the tuner. Fill out your sig with all the goodies you know you have and let's see what we can find.

Welcome to the site!