Have had this old dodge years now. First problem finally came about. 99 Dakota 3.9 160k.

Truck starts FINE on the first key bump. After drive for 1 or 2 minutes it sputters badly, almost stallls for 10seconds. Clears up then drives fine for the remainder of the journey.

Already replaced IAC and temp sensor.

not sure what else can cause this. Any advice?

 

Maybe the O2 sensor?

 

ah I forgot about the infamous O2 sensor. I’ll replace and report back. Thank you, please stand by.

 

Probably not, but is a possibility .... whens the last time you changed the fuel filter?

Only a remote possibility there is some crud floating in the line and temporarily blocks passage then clears up .... they tend to get forgotten about, might be a good time to replace it while chasing problems.

 

Fuel filter is integral to the pump module on these trucks. Not replaceable separately, nor easily.

 

Gotcha .... my 93 caravan has it on the frame and looked like it was original with 180k miles on it.

 

And I always though that was a MUCH Better idea..... why make it non-serviceable??? Has gas quality gotten so good that it doesn't come with 'junk' any more? I hardly think so.

 

Yes, forgot to mention new fuel pump and filter. This was the first item done after this weird phenomena started . It was the original 98 and I figured it was time anyway.

Checked compression and all numbers are nominal, gas pressure is per book spec, couldn’t find vacuum pressure specs, no check engine codes. Truck runs better after these changes but still stalls heavily after 1-2 drive on cold start. Then drives perfect.

New:
fuel Filter
fuel pump
thermo sensor
IAC
plugs
wires

suggested:
O2 sensor

 

Coolant or intake temp sensor, or both? Unfortunately the IAC was a waste of money as this is only function on idle. Based on your description the sputtering happens only while driving? What brand sensors? Before dropping money on the o2 make sure you buy a good one.

Would be interesting to see fuel rail pressure when this happens, along with fuel pump amperage and O2s.

You internet guys always have these fun scenarios to play with an oscilloscope, and I got to sit here and listen to it