So it all started when i went for a bid ride, the truck ran fine and then on the way back home i started to loose cylinders.

The only cylinders that get hot are 1,3,4,7
#5 get warm and 2,4,6,8 are cold
and she backfires through the intake.

I plugged my OBD2 code reader up to it and the only code i get is p0031

The truck has fuel pressure(40psi)
all cylinders have spark/fuel going to them
all cylinders have pressure (~150psi),
I've change the distributor cap, changed cam positioning sensor and i also checked the timing and it's dead on.

tomorrow i will change the crank positioning sensor

2001 Dakota R/T 5.9l

Thanks in advance - Kyle

 

Are the plugs wet? How do you know the fuel injectors are firing?

Timing cannot by adjusted on our trucks, the cam sensor within the distributor has to be synced to within +/- 5 degrees of the cam sensor ("Fuel Sync").

Have you checked for bad catalytic converter?

 

40 psi? Your fuel pressure is low.

Spec is 49.2 +/- 5.

 

plugs are wet, and im running no cats

 

I will look into a new fuel pump

 

You tested for spark using a screwdriver or holding a spark plug against a ground, yes?

If so, the only way the plugs can be wet in presence of spark is that the fuel sync is off by a mile.

 

Agree with Magnethead on the fuel sync.

Did you turn the distributor at all?

 

Yes i tested the spark against the ground it's nice and blue.

No i did not turn the distributor at all, i did test the fuel pressure once again and at idle the gauge is jumping like crazy from 40-50psi.
Im gonna replace the fuel pump today and see what happens

 

p0031 is a bad o2 sensor bank 1, this is likely your problem and not the fuel pump, even though the fuel pump probably does need replaced, its not going to cause wet plugs like an o2 sensor would..

 

I jacked the truck up this morning and saw a O2 sensor was unplugged, so thats ruled out


I got a new fuel pump and installed it, i have a lot more fuel pressure now, but still down a few cylinders :/