Please help.
My Check Engine Light has come on and I have determined that it was caused by Diagnostic Trouble Code P0171, System too Lean. There are no other codes and the car behaves normally in every respect.
I don't believe I have a vacuum leak as the idle speed is correct.
I don't believe the problem is low fuel pressure as the car has normal acceleration and does not bog.
My theory is that I have a lazy Air/Fuel sensor (not called O2 sensor for California emissions). It seems to me that the only feedback the emissions control computer has that would cause a lean trouble code is the Air Fuel sensor.
There is one more piece of information, the Fuel Trim indication was
-11%. I am hoping that I can get some technical advice before I spend $240 on a replacement Air/Fuel sensor.
Thanks in advance.
Marvin