Code P0171 just came on in my truck. says system to lean (bank 1)...What would cause this? A O2 sensor???

Any help would be much appreciated

4.6l 1997

 

Maybe a MAF sensor??????????

 

Do a search there is a TON of stuff on this code. Most common cause seems to be the pvc elbow but there are lots of other things. search and ye shall find..

 

Being only code P0171 I would look closely at a intake or exhaust manifold leak on that side.

 

what side is bank 1? i dont know that much yet lol? is this around the intake?

 

Passenger side.

 

My 97 Expedition threw the same code. Tried the pcv line assembly since it was dry and brittle. That didn't work. Then I started throwing the code for both banks, 1 and 2. I sprayed some MAF cleaner on the MAF and the problem went away. I think the MAF cleaner was $6 or $7 at Autozone.

 

Yep! Most likley a leak - But, the MAF and PCV is the first to look at and service. Like jethat said,= "Search" Lots of info and pics.

 

alright ill have to go try some MAF cleaner. I think ill change the fuel filter as well. It might fix my low MPG problem a little

 

I agree - Maf or PCV system leak somewhere.

 

Word.

A MAF or PCV leak would trip the codes for both banks...or so I thought.