PO171, PO174 at the same times means vacuum/intake leak, it has been said close to a million times on here. Anyways spray starting fluid around the intake gaskets with the car running at idle, if the engine stumbles there is your leak, if it doesnt then you have vacuum leak.
As for P1131.....
The sensor is monitered by the PCM for switching.
The test fails when the sensor doesnt switch due to circuit or fuel exceeds a calibrated limit.
Causes the list is long brace yourself
Short to VPWR in harness or H02S
water in harness connector
open/shorted HO2s circuit
corrosion or poor mating terminals and wiring
damaged HO2S
damaged PCM
excessive fuel pressure
leaking/contained fuel injectors
leaking fuel pressure regulator
low fuel pressure
vapor recovery system
air leak after MAF
vacuum leaks
PCV system
improperly seated engine oil dipstick
leaking EGR valve gasket
stuck EGR valve
leaking diaphram or EVR
oil overfillled
cam timing
cylinder compression
exhaust leaks near or before the HO2S
Fianlly the slow response, I had a slow response once to, replaced the sensor and all was well.
Anyways basically the sensor took more than 1/100th of a second to switch from rich to lean or vice vesa.
Last edited by HITMANinMI; 11/22/04 07:07 PM.
