did a previous thread on code 12 so after my tune up on 3.9 v6 now i get the check engine light on with a code of po171 still runs a little rough with a hint of black smoke after changing everything plugs cap rotor wires air filter pcv valve oil change any ideas????

 

anyone??????

 

According to https://dodgeforum.com/forum/2nd-gen...aters-ect.html: P0171 (M) 1/1 Fuel System Lean A lean air/fuel mixture has been indicated by an abnormally rich correction factor.

According to haynes manual: P0171 System too lean (left cylinder bank)

 

any idea what the problem could be

 

If it's too lean, the first things I would start to think about are fuel delivery. If you haven't already, I would suggest picking up your haynes manual and looking through the stockpile of information it holds for your truck. It will run you about $15-$20.

[from haynes manual] Check air intake duct to the intake manifold for leaks, which will result in an excessively lean mixture

This might give you a starting point.

 

Also, the following sensors are involved in helping the PCM determine the fuel mixture: camshaft and crankshaft position sensors, Engine coolant temperature sensor, intake air temperature sensor (IAT), manifold absolute pressure (map) sensor

So each of them should be checked per steps provided in your haynes manual

 

However, because it is only tripping the left side, it leads me to believe it is something to do with just the left side. Such as injectors being hinky.

 

well got another code today po133 which is o2 sensor along with the po171 lean, i'm assuming now that i got everything within spec when tuning it up ( when i bought the truck it was puffin black smoke running little rough, plugs were at like .060 gap not the .040 it should be ) all the sensors are all carboned up now is this a possibility

 

ok left looking at the truck from the front or sitting in the drivers seat

 

Drivers side. Same side as your precat o2 sensor malfunction. I just replaced that same o2 sensor last week for the same code. Code all gone now.

I personally dont have enough experience to make a definitive informed decision about the carbon soot affecting the sensors. You could always run some engine cleaner and/or fuel system cleaner.