P0401 (EGR Flow Insufficient)
I've been chasing several issues on this truck for a while now. (Bank 1 Lean started it, replaced a lot doing that.) The most recent are the P0401 (EGR Flow Insufficient) code and the truck having a high engine speed between gears or after giving it gas while sitting static.
We just replaced the DPFE and the code came back after a couple days. Can't find any other leaks in the EGR system. Could the valve itself cause this code?
I'm not sure what the high ending speed between gears is from, other than the ECU not being able to correct for something else. The only parts I haven't replaced are the intake temperature sensor and the TPS.