P0507 Idle System High
2 Mornings (cold start) the car wont idle, just stalls but would run with extra pedal and seemed to have good power. Drove 5 miles and it was fine.
1 Night (hot) coming home the idle was extremely high (2000 RPM)
Idle seems high compared to the TECH 2 commanded idle. example command 750 but 950.
Replace the MAF with new Delphi unit.
Throttle Position appears to work fine.

P0137 HO2S Circuit Low Voltage Bank 1 Sensor 2
P0136 HO2S Sensor Circuit Low Voltage (Bank 1, Sensor 2)
When I got the car it had 2-3 bad coil packs, I assume the CAT is bad.

Any adivice?

_________________
02 SSEI, 1.94 Yella Terra,Gen5 , N*,2-1/4""Phenolic Intercooler,
I SELL, Phenolic Intercoolers, Pulley Pullers, Throttle Bodies, Etc...!!

You wasted money replacing the MAF. This is an IAC issue. This code flags when the PCM tests the IAC and it fails 3 times.

P0136 is a test to see if the HO2S 2 does not switch properly during a passive test, then if either a lean intrusive test or a rich intusive test fails. If flags this DTC

P0137 flags when that reading is below 25mV.

These two codes, a lot of testing involves testing the high signal and low signal circuits of the sensor.

I highly doubt the cat is bad.

_________________


Retired Bonneville Owner and former GM Tech:
2004 Pontiac Bonneville GXP: Black/Ebony *SOLD*

Summer Toys: Combined 827 RWHP / 877lb/ft RWTQ
2004 Pontiac GTO: Impulse Blue Metallic/Black/M6: lots 'o mods, 415 RWHP / 405lb/ft RWTQ!
2006 Cadillac STS-V: Light Platinum Metallic/Light Gray/A6 - Spectre CAI, Magnaflow exhaust, Speed Inc. tune, 412 RWHP / 472lb/ft RWTQ

Daily Drivers:
2019 Chrysler Pacifica Limited: Mommy's new RGC
2015 Chrysler Town & Country Limited Platinum: Kids new RGC
2007 Chrysler Town & Country Limited: Sold to neighbor
2009 Pontiac G8 GT: L76, Sport Red Metallic
2003 Chevrolet Suburban 2500: Doeskin Tan - 8.1L Big Block... new plow truck
1999 Chevrolet Suburban: Sunset Gold Metallic - Daddy's winter beater and plow truck

I swapped N* TB's and the idle is fixed. Either the IAC valve and/or the cracked PCV tube appears to be the culprit.

Only DTC is the P137 now. I got the car they had been running with bad coil packs. Not sure how long they ran with bad coil packs but it could have been a long time. Do you think it's the HO2s and not the CAT? What's the fix for this?

_________________
02 SSEI, 1.94 Yella Terra,Gen5 , N*,2-1/4""Phenolic Intercooler,
I SELL, Phenolic Intercoolers, Pulley Pullers, Throttle Bodies, Etc...!!

Like I say, P0507 is a IAC. Probably stuck open.

_________________


Retired Bonneville Owner and former GM Tech:
2004 Pontiac Bonneville GXP: Black/Ebony *SOLD*

Summer Toys: Combined 827 RWHP / 877lb/ft RWTQ
2004 Pontiac GTO: Impulse Blue Metallic/Black/M6: lots 'o mods, 415 RWHP / 405lb/ft RWTQ!
2006 Cadillac STS-V: Light Platinum Metallic/Light Gray/A6 - Spectre CAI, Magnaflow exhaust, Speed Inc. tune, 412 RWHP / 472lb/ft RWTQ

Daily Drivers:
2019 Chrysler Pacifica Limited: Mommy's new RGC
2015 Chrysler Town & Country Limited Platinum: Kids new RGC
2007 Chrysler Town & Country Limited: Sold to neighbor
2009 Pontiac G8 GT: L76, Sport Red Metallic
2003 Chevrolet Suburban 2500: Doeskin Tan - 8.1L Big Block... new plow truck
1999 Chevrolet Suburban: Sunset Gold Metallic - Daddy's winter beater and plow truck

You were right on the money.


How about the HO2s code ? Would driving with bad coil packs take out the CAT or do you think it's the Sensor

_________________
02 SSEI, 1.94 Yella Terra,Gen5 , N*,2-1/4""Phenolic Intercooler,
I SELL, Phenolic Intercoolers, Pulley Pullers, Throttle Bodies, Etc...!!

It was the rear O2 not the CAT. It was the cheaper option to try and definitely see much more action on the mili Volts and no codes.

_________________
02 SSEI, 1.94 Yella Terra,Gen5 , N*,2-1/4""Phenolic Intercooler,
I SELL, Phenolic Intercoolers, Pulley Pullers, Throttle Bodies, Etc...!!