I'm working on a 2001 dodge dakota 3.9L V6. When I start it and it does not matter what time of day, it does not hardly want to run when you put it in gear. At first it idles poorly then when I put it in gear and step on throttle, it spits, sputters, and will back fire through intake. Now once I push pedal to floor, it comes out of it and will run fine usually. It does not do it everyday, but somedays are worse than others. Fuel pump pressure is good, it does not leak down. It has new plugs, wires, cap and rotor, new coil, and IAC motor. It has no vaccum leaks that I can find. I also checked for leaks around intake and did not find any. It also does not throw any codes when it starts running like crap. Is there something that I am overlooking, and could somebody point me in another direction, please? Thanks

 

did you check your plenum gasket?

 

Welcome to DF

Could be also a timing chain, But you really should do a compression test and post. Is the check engine light on?

I will move you post to the 2nd gen dakota section.

 

I sprayed carb cleaner around plenum and got no change in way engine ran. I will do a compression test but would the engine not run like crap everytime I started it if it had bad compression? Also, the check engine light never comes on when it is spitting and sputtering.

 

O2 sensors?

I had a backfire and posted a video on this forum. Search "backfire from hell". It was backfiring through the intake and it turns out it was a bad o2 sensor.

 

i know it seems simple and stupid but how is the PCV valve look??

 

Thanks for all the leads. Ended up having to replace both upstream o2 sensors. Truck runs great. Again thanks