DreamerGT

the light just came on I pulled these

P1131 Lack Of HO2S11 Switch - Sensor Indicates Lean

P1151 Lack Of HO2S21 Switch - Sensor Indicates Lean

ct_white_stang

It sounds like the long-tube syndrone....been there done that

DreamerGT

I dont understand whats wrong with my longtubes?

ct_white_stang

It could be something else wrong but when you did your long tubes did you get a tune for them? They move the O2's downstream which can cause this code. I was getting this too originally when I installed mine. Here is all the other crap it could be though. Check the underlined ones first.

Electrical:
Short to VPWR in harness or HO2S
Water in harness connector
Open/Shorted HO2S circuit
Corrosion or poor mating terminals and wiring
Damaged HO2S
Damaged PCM
Fuel System:
Excessive fuel pressure
Leaking/contaminated fuel injectors
Leaking fuel pressure regulator
Low fuel pressure or running out of fuel
Vapor recovery system
Induction System:
Air leaks after the MAF
Vacuum Leaks
PCV system
Improperly seated engine oil dipstick
EGR System:
Leaking gasket
Stuck EGR valve
Leaking diaphragm or EVR
Base Engine:
Oil overfill
Cam timing
Cylinder compression
Exhaust leaks before or near the HO2S(s)

cliffyk

In closed loop the PCM expects changes it makes in AFR to be read by the front sensors in after a specific delay that is set in the O2 Transport Delay table. This table specifies a delay time in seconds for load vs. rpm. Stock values range from 0.602s at 10% load and 1000 rpm, to 0.133s at 70% load and 3500 rpm.

When the sensors are relocated further away from the exhaust ports these values need to be increased.

DreamerGT

I have had my longtubes on for almost 3 years now, so I dont know why something would come up now. I will check out the things on that list.

DreamerGT

anybody else?

cliffyk

As O2 sensors age their response time slows...