I replaced the upper and lower intake manifold gaskets, replaced all 4 O2 sensors, sprayed carb cleaner all over any rubber/plastic hose, replaced the PCV valve and fuel filter, spark plugs....What could be causing this CEL to occur? This is driving me nutz....
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Only getting 0171 code
- Thread starter pakman84
- Start date
twocontours
CEG'er
Diagnostic Trouble Codes (DTCs) P0171 bank (1) (cylinder #1) and DTC P0174 bank (2) indicate the fuel/air ratio is too lean. The fuel adaptive system is at the rich correction limit.
DTC P0172 bank (1) and DTC P0175 bank (2) indicate the fuel/air ratio is too rich. The fuel adaptive system is at the lean correction limit.
DTCs HO2S Reference list:
-- HO2S-11 = DTCs P0171 and P0172
-- HO2S-21 = DTCs P0174 and P0175
Possible causes:
Fuel system
-- Excessive fuel pressure.
-- Leaking fuel injector(s).
-- Leaking fuel pressure regulator.
-- Low fuel pressure.
-- Contaminated injector(s)
Induction system
-- Air leaks after the MAF.
-- Vacuum leaks.
-- Restricted air inlet.
-- PCV system.
-- Fuel purge system.
-- Improperly seated dip stick.
EGR
-- Leaking gasket.
-- Stuck open EGR valve.
-- Leaking diaphragm.
Base engine
-- Oil overfill.
-- Cam timing.
-- Cylinder compression.
-- Exhaust leaks before or near the HO2S's.
l Check air intake for leaks, obstructions and damage.
l Check air filter, air filter housing for blockage.
l Verify integrity of the PCV system.
l Check for vacuum leaks.
l Are there any of the above concerns?
Yes
SERVICE as necessary. RERUN «Quick Test».
DTC P0172 bank (1) and DTC P0175 bank (2) indicate the fuel/air ratio is too rich. The fuel adaptive system is at the lean correction limit.
DTCs HO2S Reference list:
-- HO2S-11 = DTCs P0171 and P0172
-- HO2S-21 = DTCs P0174 and P0175
Possible causes:
Fuel system
-- Excessive fuel pressure.
-- Leaking fuel injector(s).
-- Leaking fuel pressure regulator.
-- Low fuel pressure.
-- Contaminated injector(s)
Induction system
-- Air leaks after the MAF.
-- Vacuum leaks.
-- Restricted air inlet.
-- PCV system.
-- Fuel purge system.
-- Improperly seated dip stick.
EGR
-- Leaking gasket.
-- Stuck open EGR valve.
-- Leaking diaphragm.
Base engine
-- Oil overfill.
-- Cam timing.
-- Cylinder compression.
-- Exhaust leaks before or near the HO2S's.
l Check air intake for leaks, obstructions and damage.
l Check air filter, air filter housing for blockage.
l Verify integrity of the PCV system.
l Check for vacuum leaks.
l Are there any of the above concerns?
Yes
SERVICE as necessary. RERUN «Quick Test».
2X95SEs
CEG'er
My O-rings in the holes where the power brake and vacuum line tap into the intake manifold were all dried up and broken. Did you also replace the gaskets for the EGR and TB when it was apart? Clamp on the rubber bellow to the TB tight?
zorrex
Enjoys the Abuse
Clean you MAF! Just a little bit of isopropyl alcohol will do the trick, but be careful! It worked for me 
Wow talk about quick input-One of the first things I did was remove the MAF and spray it with "the radio shack" contact cleaner and nothing changed after that. With the issue being on bank 1, how could there be an issue in any of the other common systems that involve bank 2?
zorrex
Enjoys the Abuse
This may be SUCH a dumb question to ask because it sounds like you know what you're doing, but did you reset the computer (a.k.a. pulling off a battery cable for a prolonged period of time
) after doing all your fixes??