dirtk38
New Member
Hello All,
I'm wrestling with codes P0172 and P0175 (rich condition on both banks) on my 2006 Tahoe (with FlexFuel), so I thought I'd join your forum and see if I could find any good ideas on things to check. Here's what I've done so far:
-Verified long-term fuel trim is around -19.5% for both banks, at all speeds
-Did a fuel system pressure test, didn't seem to be any leaks and pressure was good (around 58 psi)
-Replaced MAF sensor, even though my scanner showed airflow readings within the specified range
-Verified that both O2 sensors are fluctuating between .2.8 V (per service manual), but I did notice that sometimes they go below .2V
My vehicle has about 105k miles and is completely stock except for K&N air filter. The only driving symptoms I've noticed are decreased fuel economy (lost about 2 MPG) and engine stumbling for 1 or 2 seconds when starting. It seems all this started when the weather began to cool off last month, but that may be a coincidence.
Anyone have suggestions on what to check next? I know O2 sensors are a common culprit, but my thought is that since I'm getting errors on both cylinder banks, its not likely that both sensors are failing at the same time. I'm no expert though, so feel free to correct me. Thanks!
I'm wrestling with codes P0172 and P0175 (rich condition on both banks) on my 2006 Tahoe (with FlexFuel), so I thought I'd join your forum and see if I could find any good ideas on things to check. Here's what I've done so far:
-Verified long-term fuel trim is around -19.5% for both banks, at all speeds
-Did a fuel system pressure test, didn't seem to be any leaks and pressure was good (around 58 psi)
-Replaced MAF sensor, even though my scanner showed airflow readings within the specified range
-Verified that both O2 sensors are fluctuating between .2.8 V (per service manual), but I did notice that sometimes they go below .2V
My vehicle has about 105k miles and is completely stock except for K&N air filter. The only driving symptoms I've noticed are decreased fuel economy (lost about 2 MPG) and engine stumbling for 1 or 2 seconds when starting. It seems all this started when the weather began to cool off last month, but that may be a coincidence.
Anyone have suggestions on what to check next? I know O2 sensors are a common culprit, but my thought is that since I'm getting errors on both cylinder banks, its not likely that both sensors are failing at the same time. I'm no expert though, so feel free to correct me. Thanks!
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