[Crashly]

Hi everybody I was hoping for a little help here. I have been chasing this ghost for a couple of weeks. I started having a problem a few weeks ago, truck would start great and idle great, when I would go up my hill it would buck and hesitate and have a rough idle. I would have to put it back into neutral and wait a few seconds for the idle to even back out. It reminded me of a fuel starvation problem. I installed a new lift pump and new fuel filters (1 aftermarket spin on directly after tank). Still did not solve the problem. I dropped the tank and inspected the pick up (inside filters have been deleted) everything was perfect. I put a vacuum on the fuel pickup line, it held vacuum. Hooked it up to my AE and I couldn't find any glaring problems, however truth be told, I really am not well versed on how to decipher and use the various functions and senors that the AE reads (the truck never breaks down). I pulled the fuel regulator and found that it was dirty. The bronze piece center hole was clogged so I cleaned it up and reinstalled everything. Switched out my CPS to one of my spares , (it now idles rougher). I found a little oil in the IPS connector, so I replaced it, wiring harness still looked good. UVC, injectors, glow plugs, and wiring harness replace 20K ago, oil changed 2500 miles ago. So here is what my latest test is showing. While in neutral, with engine warm, I depress, the accelerator and hold at 2k, after a few seconds it starts stumbling and rpms drop (over a few seconds) to around 600-800 rpm (fills like a miss is also happening when this happens) then the idle comes back up to 2ooo rpm, hangs in there a couple of seconds and then goes back down. The cycle will just keep repeating itself over and over. Any suggestions or tips would be appreciated.

 

[crashz]

I'm no expert, but have a few questions:

- Have you checked fuel pressure? Seems like a delivery issue to me.
- Is the CEL on?
- How about fuel flow? Condition of the fuel filter / bowl? If the regulator had stuff in it, did the bottom of the fuel bowl collect anything?