I have a 97 f150 with a 4.2 in it I did a open air intake mod and i changed the oxygen sensors,egr valve,the egr relay, and i cleaned out the intake system the throttel body and the mass air flow sensor and I'm still getting a back fire out of the throttel body. I'm also receiving edbII codes of 172,174,and 304 I checked the vacume lines with no leaks found. It runs rough at a idel and hesatates when I try to pull a way from a stop. I sea foamed the engine. Any help will be appreceated

 

Welcome to the forum

How many miles on the spark plugs?
The P0304 is a misfire, quite likely caused by a bad plug or wire.
The P0172 means that bank 1 (passenger's side) of the engine is running too rich.
The P0174 means that bank 2 is running too lean.
Have you checked for vacuum leaks?

 

The plugs only have about 500 miles on them I moved the plyg and wire from the # 4 and I still have the code. I've checked for a vacum leak unless I'm missing a line I can't find one. I'm thinking about pulling the plug and cleaning it. If I clean The maf it clears up for short time.

 

Sounds like too much oil on the new filter.

 

would this give me a fault message of 0172 0174. I hope this is all it could be. so i should clean the filter and oil it ?