My 01 windstar keeps throwing 2 codes. P0171 (system lean bank 1) and P0174 (system lean bank 2) What could be some possible causes . It runs fine no loss of power or hesitation what so ever. I'm thinking maybe O2 sensor, clean maf sensor, clean throttle body, and ???? Any advice I can get would be appreciated.

 

Leak on the intake air piping maybe?

 

Took it to a friends garage since I have no free time. Got the call today it's the intake gasket leaking by cylinder 1.

 

I guess it's good that the problem is found, would be better if it was just a vacuum line though.

 

Suggest you go to AutomotiveForums.com and search the Windstar forum. Very common problem--pretty sure you're supposed to replace all the isolator bolts and the front valve cover when you do the gasket. Not for sure if this pertains to 2001 or not.

 

Intake gasket set was changed definate crack in it. Bad news was it still was missing. After a fair amount of testing the coil was found to be weak on the towers for cylinders 1 2 3. The 4 5 6 towers showed full juice, slapped a new coil on and tada fuel milage is back and runs great again. Gets the wife back in a better mood. So now I can get back to working on the 78 in my sig.