1997 5.4 Running Lean
 

So ive had a check engine code on for my emissions, got it fixed never cleared the code, went to clear the code today and had 2 more codes. P0171 System Too Lean Bank 1 and P0174 System Too Lean Bank 2.
I belived that bank 1 is driver side and bank 2 is pass side.
So im thinking fuel pressure,or dirty injectors... going check that out but wondering if any thing else i might wanna check,
not sure when then code came on hope nothing got fed up :unsure:

bank one is passenger. bank 2 driver. O2 sensors??

Or Something:
 

:unsure: If not EGO sensors, then possibly a vacuum leak. How much mileage is on the machine? EGO sensors generally last well beyond 100K. :huh:

has new o2 sensors when i put the new exhaust on, it has about 140k i check the fuel pressure was 30lbs at idle and jumped to 40 when vac line was disconnected, changed fuel filter, no change in fuel pressure after filter changed.Cleared the codes put 300 miles on no codes....working so far... but isnt 30lbs a lil low?

Within Limits:
 

:thumbsup: Fuel pressure: KOEO, 30-45psi; KOER, 27-42psi.

30psi is within limits, but on the low side. I wouldn't be concerned about it. The PCM will compensate by adjusting the injector on-time. My '97 4.6L has almost the same readings as you are getting. :thumbsup:

You might try resetting the PCM by removing momentarily the negative battery connector. The system will then need to go through a driving cycle to recover all the operating strategies. :)

Look for a vacuum leak in a hose common to both banks. I had a hose that went into the intake tube leak and give me those codes.

ok sweet sweet, im fine with that 30lbs then :D, Everythings still smooth no codes :)

spoke too soon......was driving it today came on getting p0171 bank 1 lean, and a pend p0174 too lean bank one...what the differnce between a code and a pend? never knew...so now idk what to do,leaving monday for a 1,000mile trip to ride bike, and dont wanna be going that way running lean >.<

My 03 did the same thing about a month ago. Mine was a bad egr senscor. Not the vale.

I dont think it be that, i replaced teh egr sensor and the egr last year.....i do have header leak cuz the gaskets blew out, putting on dead soft gaskets on tonight i dont kno if the leak would cause it to run lean?