Re: P0171 bank 1 too lean

On 2/27/25 7:45 PM, Isaac Montara wrote:

I have a Mitsubishi Lancer ES early 2000s with a P0171 that keeps coming
back after I reset it with an OBDII hand-held code reading tool.
 I put new spark plugs in and it still sets the P0171 bank 1 too lean.
When it idles, it often kills the motor so it's not getting enough fuel I
think.
 But I don't know cars all that well. How do I increase the idle RPM on an early 2000s Lancer ES?

Have you tried putting a fuel system cleaner in the gas tank, and then driving the car for awhile  to see if code stops ?