I'm having fits with the check engine light. My 2000 Ranger is showing DTC's 171 and 174 which indicate that the engine is running lean. I subscribe to Alldatadiy online diagnostic service and have run their suggested tests to no conclusion.

I checked all hoses, fittings and gaskets for leaks - found none
Tested fuel pressure - it's Ok
Mass air flow sensor - appears OK

Here is the strange thing that I am finding. I have an engine scanner and it indicates that the barametric pressure sensor is reading much lower than it should (22 in Hg as oppose to 30 in Hg). They have a specific test to do on this sensor but I'll be dammed if I can find it. Alldatadiy gives not-a-clue to where to find it.

Does this truck have a separate barometric pressure sensor or is it part of some other part or sensor? Anyhelp with this would be greatly appreciated.

Any thought on what to check to fix these code would also be appreciated