Recurring P0171 Code - bigger problem
Thread Starter
Driver School Candidate
Joined: Oct 2012
Posts: 3
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From: Georgia
Recurring P0171 Code - bigger problem
Hey, looking for some insight and suggestions on what may be going on with my 1999 RX. I have been reading this forum and searching the forum, but I think my issue is a little different.
About 2 years ago, my check engine light came on and I pulled P0171 bank 1 o2 sensor
P1155 mfg fuel air meter. I changed the MAF and both O2 sensors and thermostat. About 6 months later, I received a P0171 and P0300 Multiple missfire, and had my mechanic look at it, the catalytic converter was cracked and he said the engine was not burning all the gas, and the catalytic converter was overheating (said it was glowing red when I brought it in). We replaced the catalytic converter, replaced the spark plugs and i put in a new bank one sensor (the one on the front of the engine).
I started getting 26-27 miles per gallon when I had previously been getting 17-19 MPG. Something is wrong, and again yesterday the check engine light came on and I have a P0171 (Bank one system too lean) code.
I think maybe some of the cylinders are not firing or something else. Any suggestions or things I need to do? I am taking it to the lexus dealer to do a diagnostics for 120$ but I want to make sure they really diagnose it instead of just pulling the code.
160K miles
K&N air filter (Oiled one)
Changed MAF sensor
Changed both O2 sensors
Tightened up belts etc.
Any help or suggestions would be appreciated.
About 2 years ago, my check engine light came on and I pulled P0171 bank 1 o2 sensor
P1155 mfg fuel air meter. I changed the MAF and both O2 sensors and thermostat. About 6 months later, I received a P0171 and P0300 Multiple missfire, and had my mechanic look at it, the catalytic converter was cracked and he said the engine was not burning all the gas, and the catalytic converter was overheating (said it was glowing red when I brought it in). We replaced the catalytic converter, replaced the spark plugs and i put in a new bank one sensor (the one on the front of the engine).
I started getting 26-27 miles per gallon when I had previously been getting 17-19 MPG. Something is wrong, and again yesterday the check engine light came on and I have a P0171 (Bank one system too lean) code.
I think maybe some of the cylinders are not firing or something else. Any suggestions or things I need to do? I am taking it to the lexus dealer to do a diagnostics for 120$ but I want to make sure they really diagnose it instead of just pulling the code.
160K miles
K&N air filter (Oiled one)
Changed MAF sensor
Changed both O2 sensors
Tightened up belts etc.
Any help or suggestions would be appreciated.
Last edited by blakedawg; Oct 1, 2012 at 12:33 PM.
Instructor
Joined: Oct 2005
Posts: 1,090
Likes: 129
From: pa
Hey, looking for some insight and suggestions on what may be going on with my 1999 RX. I have been reading this forum and searching the forum, but I think my issue is a little different.
About 2 years ago, my check engine light came on and I pulled P0171 bank 1 o2 sensor
P1155 mfg fuel air meter. I changed the MAF and both O2 sensors and thermostat. About 6 months later, I received a P0171 and P0300 Multiple missfire, and had my mechanic look at it, the catalytic converter was cracked and he said the engine was not burning all the gas, and the catalytic converter was overheating (said it was glowing red when I brought it in). We replaced the catalytic converter, replaced the spark plugs and i put in a new bank one sensor (the one on the front of the engine).
I started getting 26-27 miles per gallon when I had previously been getting 17-19 MPG. Something is wrong, and again yesterday the check engine light came on and I have a P0171 (Bank one system too lean) code.
I think maybe some of the cylinders are not firing or something else. Any suggestions or things I need to do? I am taking it to the lexus dealer to do a diagnostics for 120$ but I want to make sure they really diagnose it instead of just pulling the code.
160K miles
K&G air filter
Changed MAF sensor
Changed both O2 sensors
Tightened up belts etc.
Any help or suggestions would be appreciated.
About 2 years ago, my check engine light came on and I pulled P0171 bank 1 o2 sensor
P1155 mfg fuel air meter. I changed the MAF and both O2 sensors and thermostat. About 6 months later, I received a P0171 and P0300 Multiple missfire, and had my mechanic look at it, the catalytic converter was cracked and he said the engine was not burning all the gas, and the catalytic converter was overheating (said it was glowing red when I brought it in). We replaced the catalytic converter, replaced the spark plugs and i put in a new bank one sensor (the one on the front of the engine).
I started getting 26-27 miles per gallon when I had previously been getting 17-19 MPG. Something is wrong, and again yesterday the check engine light came on and I have a P0171 (Bank one system too lean) code.
I think maybe some of the cylinders are not firing or something else. Any suggestions or things I need to do? I am taking it to the lexus dealer to do a diagnostics for 120$ but I want to make sure they really diagnose it instead of just pulling the code.
160K miles
K&G air filter
Changed MAF sensor
Changed both O2 sensors
Tightened up belts etc.
Any help or suggestions would be appreciated.
Thread Starter
Driver School Candidate
Joined: Oct 2012
Posts: 3
Likes: 0
From: Georgia
Lexus Test Driver
Joined: Aug 2009
Posts: 5,723
Likes: 114
From: NJ
That may be the reason why you have the P0171. The oil off of the filter is accumulating onto the MAF sensor. You need to clean the oil off the MAF by cleaning it, and put back the OEM filter or don't put so much oil on the K&N.
Thread Starter
Driver School Candidate
Joined: Oct 2012
Posts: 3
Likes: 0
From: Georgia
What about the MPG being 26-28 MPG? Does that indicate something else is going on? The catalytic converter being replaced because the fuel was not burning out, so I am wondering if it is something with the engine or fuel etc.
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