Whats Next
 

Ok Last week I wrote about Idle problems, and try various fixes heres what has been done

First the car is a 2004 Gt, Has streen racing stage 2 heads, comp 270 cams, SCT Custom tune, Longtube headers, 70 MM throttle body & plenum, 4:10 gears.

It started Idleing ruff and then got to the point where it would rev about 1500 rpms then drop way low then shoot back up, then to where it would Idle for 30 seconds and shut off.

I have cleaned the MAF, replaced the IAC, Replaced the PCV

The code is P21107< o2 sensor I have put two different one in, I just finished replacing the o2 sensor, had the battery disconnect, use a diablo tuner to clear the code, It seem to ilde ok took it for a ride seemed ok parked it, went back out about 10 mins later start the car and the check engine light is back on reading o2 sensor

Same code?

Yeah
 

Same code

I cant find P21107.

oops
 

I fat finger it P2197

P2197
Lack of HO2S-21 Switch, Sensor Indicates Lean
Detailed Description
A heated oxygen sensor (HO2S) indicating lean at the end of a test is trying to correct for an over-rich condition. The test fails when the fuel control system no longer detects switching for a calibrated amount of time.
Possible causes :-
Electrical:
# Short to VPWR in the harness or HO2S.
# Water in the harness connector.
# Open/shorted HO2S circuit.
# Corrosion or poor mating terminals and wiring.
# Damaged HO2S.
# Damaged powertrain control module (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 mass air flow (MAF) sensor.
# 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).