i pulled these codes today and im not sure where to start looking for the problem.

po172-system to rich bank 1

po175-system to rich bank 2

i was thinking mass air flow sensor but the guy at t he parts place told me it could also be my o2 sensors.im not sure about that as i would think the o2 sensors are doing there job and reading the rich condition.

any ideas ?

thanks.

 

Find a better scan tool you can borrow and watch the o2 sensors. You want to see them move from .00 all the way to 1.0 for a split second at wot. If they won't move above a .5, they are at fault. I don't remember, don't you have a sensor on each bank and one before or after the cat?


Another possibility is the fuel pressure regulator, it may be allowing more fuel than you need.

Usually when the maf goes it causes the engine to go haywire and run very erratic all over the rpm and driving range, but anythings possible.


To start, first thing, check the air intake. The filter and the box, you want to make sure the engine isn't air restricted, but usually when they are the o2 sensors will correct the issue. That's what they're there for.

 

thanks, the air box is clean and the filter is brand new.

 

I second AG's suggestion to check the fuel pressure regulator. If the diaphragm is broken it'll allow raw fuel to flow into the intake manifold, giving a rich condition. Just pull the vacuum line going to it and see if it's wet from fuel inside.

 

thanks guys, i will check that out.

maybe this information will help also.

none of these codes or problems started till i drowned the truck in a mud crossing at a local 4x4 park.it sucked in water from the air intake and was stalling out and sputtering.

so i was thinking if it didn't do it before that maybe sucking in the water through the air intake damaged the mass air sensor ?