Ford Expedition

"" wrote: > HELP. I have two codes (P0171, P0174) that keep appearing on > the scanner > for a 1998 Ford Expedition 5.4 engine, 4-wheel drive. Can > anyone tell me > what the underlying cause of this is. Thanx.

P0171 Bank 1 lean code P0174 Bank 2 lean code. Their are several things that could cause this code their is a vacuum leak typically behind the intake manifold a vacuum line is split or deterroriated very difficult to get at second thing is the MAF sensor is dirty remove the air cleaner housing remove the inner part of the housing you will have to disconnect a connector to remove once removed you will see a 2 wires thin which senses the air entering the eng if these wires are dirty the processor thinks that too much air is entering the eng and will lean out the fuel air mixture accordingly take alchol and a acid brush and clean these wires It may take a couple of miles but your eng will run better if you have a scan tool the maf sensor reading should be at