Expert: Kevin Pilotte - 5/24/2006

Question

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Followup To

Question -
My check engine light came on two weeks ago and the computer said it was code P0171(system to lean-blank 1)So the mechanic changed the oxygen sensors, then the next day the light came on again and the computer said it was code P0137(O2 sensor circuit low voltage, Blank 1 Sensor 2)How could I correct this problem, the mechanic keeps giving me the runaround. Could it be the spark plugs or battery?? Thanx

Answer -
Though my specialty is vehicles manufactured by American Motors Corporation prior to 1981, (pre OBD vehicles) I will try to answer your question.
But I need more information.
What year, make and model vehicle do you have?
What engine & transmission is it?
How many miles are on it?
Let me know so I can better diagnose your problem.
Kevin

I have a 2002 Chevy Impala,3400 V6,204 CID,automatic transmission with 65,000 miles. I also noticed gray sludge under the radiator cap and when I changed my air filter a couple of months ago, I didn't put it back on correctly, there are little spaces where air can get in and my spark plugs are old. Could this be the problem? Thanx  

Answer
Joe,
Worn spark plugs and a loose radiator cap will not set a P0137 code. There are other areas that can. Unfortunately, in order to properly diagnose the problem, you need a scan tool and a digital Voltmeter. I have two pages of a diagnostic flow chart for your Impala. If you give me your email address, I will forward them on to you. Send it to my email. kepilotte@yahoo.com
Kevin