Just scanned and P0171 came up. Lean Bank 1.

just the 1 error code, I have tried a search, but suggestions were all over the place.

What is the usual culprit for a P0171?

New Motocraft plugs, wires and PVC valve 3 months ago.

99 4.6L 2WD

thanks.

 

....

 

Check for vac leaks.

 

The hose that runs from the PVC valve to the back of the manifold?

 

Yep. Also, if you didn't use a Motorcraft PCV valve, get one.

 

Yep, clean the MAF and make sure you haven't any air intake leaks. - Like at the IAT grommet. You can also check you intake gaskets with propane.

 

At that age a little fuel injector cleaner wouldn't hurt either and a new fuel filter.

Just a few maintainence items to add to the above.