2001 Dodge Ram 2500 4x4 5.9 gas

I could use some help here, truck runs rough. I have changed plugs, wires, cap, rotor, pvc.

Im also getting a po171 code

It was throwing a multi cylinder misfire codes.

When I look at the live data on my scan tool, the spark advance is jumping all over the place??? Im kind of new at this, the fuel trim levels seem out of wack as well.

Also the transmission is clutching between first and second gear. It isnt slipping. I tightened the belts and changed the fluid and filter.

Im not sure what my next step is if someone has any ideas, im all ears

 

Manual or automatic trans?

Fixed the plenum yet? (see the sticky at the top of this forum)

Unplug the front O2 sensor, take it for a drive. Run any better?

 

Hi and thanks for responding. I will unplug the front o2 sensor and drive it.

Its an auto. Fairly certain 46re

 

My computer decided to fail to go along with the truck issues. Ok finally ready to update.

So I disconnected the front o2 and no change. I decided to change out the IAC valve it was severely carbonized. No change.

So Ive done the pvc, plugs, cap, rotor, Iac,

The truck has poor idle but doesn't die. Im not getting any spark knock but do hear what sounds like air sucking when i shift into gear.

I changed out the govenor pressure plate solenoids and fixed the shifting problem. Tranny is great. Engine has a ton of carbon on the tail pipe which looks eroded. Im not really eating oil and im not getting knock so wouldn't the plenum be okay???

 

Plenum is a know failure point, and needs to be checked, at the very least. If you see oil in the intake, its failed.

Could try a cylinder balance test..... Just disconnect the injector for each cylinder, one at a time, and see which cylinders give the least RPM drop. Those will be the bad ones.