Alright, so I have an 08 Chrysler Town and Country 3.8L with a P0171 Lean bank 1 code. When everything is cleared and engine is started cold the short term fuel trims immediately go to over 30, once vehicle goes into closed loop the long terms peg high to over 30. I have checked fuel pressure - even have replaced the pump (fuel pressure is 58psi) I have even tried running engine on a motor vac (supplemental fuel eliminating the possibility of someone using flex fuel or something like that) I have replaced the fuel injectors and the fuel rail and have had both sets of injectors flow checked. I have replaced both upstream and downstream 02 sensors, I have checked for vacuum leaks and even replaced upper and lower intake manifold gaskets (have blocked off every vacuum control component off the intake to no change in the fuel trims) - have checked the coolant temperature sensor (was reading good but still replaced it) - have replaced the MAP sensor, even took the vehicle to the dealer to have the computer software updated. Thought maybe timing or PCM but don't wanna pull the trigger on one of those? PCM readings show timing "in sync" but shows 4% off, always understood that has to be over 7% in order to be a tooth off on timing ( maybe timing just stretched - but shouldn't cause these fuel trims???) Van only has approx. 130,000 miles on it - This van is kicking my ***. Anybody with any insight is appreciated

 

pcv valve is on bank 1 spray brake cleaner in areas and listen for the rpm to jump that will be your vac leak area

 

On these vans even though they are 6 cylinders the exhaust coming off the manifold leads into only 1 upstream oxygen sensor so I don't think it could even set a bank 2 lean code considering only the 1 upstream o2 and I have eliminated all vacuum components coming off intake by removing hoses and plugging them still resulting in high fuel trims. Also have used smoke tester in intake system to check for vacuum leaks and sprayed about 3 cans of carb clean on everything trying to see some change in readings. Nothing has helped.

 

not sure where you are getting the info to only having 1 upstream o2 sensor that was old tech anything after 98 uses 2 up 2 down.

here is the info for p171 for you

 

This is a picture of the exhaust. There is no oxygen sensor in the front of the engine. Only 1 upstream in the rear.

 

Also, no matter where you lookup the oxygen sensors as if you were to buy they only list a bank 1 sensor 1 and a bank 1 sensor 2

 

ahh i see now the California one has 4 federal has 2