Get the lazy oxygen sensor back to work
Dear Doctor: I have a 2007 GMC Envoy with 115,000 miles. The dash light - indicating code p0171 - comes on during long rides and sometimes goes out, but comes back on again with local driving. In the past two months, I have had multiple cylinder misfirings; I switched coils and it didn't come back. I did a tune-up, cleaned the throttle, and changed the front oxygen sensor. Have you seen this before? JimDear Jim: It appears to be related to part throttle at cruising speed. The technician can connect a quality scan tool and go to freeze-frame memory to view all of the computer inputs to ...