2001 ford explorer sport trac codes

[mustangrfast88]

ok need some help with some codes and what would cause them i got a po171 and a po174 and says lean on bank 1 and 2 and then a po304 which is a misfire cylinder 4

[graysonracin]

usually the intake gaskets, they are almost orings, usually cause some rough running if they are bad enough and the check engine light to come on wit those codes. Just my experience though, someone else may say different.

[Black Horse]

Swap your plug coils around to see if it follows, you may have a coil that is about to take a dump.

[bangingears]

ok need some help with some codes and what would cause them i got a po171 and a po174 and says lean on bank 1 and 2 and then a po304 which is a misfire cylinder 4


#1 cause is a hole in the 90 degree pcv hose where it enters the intake manifold