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2006 chevy trailblazer_ls
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4 Posts
Discussion Starter · #1 ·
last night, i changed my oil & air filter - after driving 20 miles todday, check engine light came on. Checked code:
P0171 - running lean? Any ideas would be appreciated.
 

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2006 chevy trailblazer_lt
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179 Posts
First off, running lean, means that there is more air than fuel in the mixture, going into the cumbustion chambers. The first thing I would check, would be the oil level and pressure, what is the gauge reading, and what is the dipstick showing. If you look at the exhaust, is there a color to it or not. Is there a rough idle as well, maybe it is just an O2 sensor that needs to be replaced. I think we need more information, in order to help you.
 

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2006 chevy trailblazer_ls
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4 Posts
Discussion Starter · #3 ·
-oil level & pressure are good, no exhaust problens - only 26k on engine - i am assuming that the running lean has more to do with the air filter replacement than the oil change, but i checked all hoses etc & all are good also
 

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2002 olds bravada
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2,369 Posts
might just be an oxygen sensor that coincidentally went bad at the same time as the oil change..
 

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2003 gmc envoy_slt
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Go back and make sure all hoses are connected to the air intake from the filter to the throttle body. and that the air filter cover is in place. If the trouble started after the filter change you me have knocked off a hose. Also if the filter was really bad, putting on a new one may have tricked the PCM into thinking it is running lean. Either disconnect the battery for a half hour to reset the PCM or just live with the light for a few days and it should reset itself.:m2:
 

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2006 chevy trailblazer_lt
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179 Posts
Go back and make sure all hoses are connected to the air intake from the filter to the throttle body. and that the air filter cover is in place. If the trouble started after the filter change you me have knocked off a hose. Also if the filter was really bad, putting on a new one may have tricked the PCM into thinking it is running lean. Either disconnect the battery for a half hour to reset the PCM or just live with the light for a few days and it should reset itself.:m2:
:iagree: How dirty was the filter, when it was changed? Also, maybe a throttle body cleaning is needed. A dirty throttle body, causes a lot of problems, that shouldn't be there! Anyway, let us know and have a great Fourth of July!
 

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2002 chevy trailblazer_ls
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Shot in the dark here, but make sure the person that did the oil change did not spill oil on your cam shaft sensor. It's located like right below where you pour the oil in and if oil is spilt it runs right onto it which may cause the light to come on.
 
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