XPost: alt.home.repair   
   From: xenolith@optusnet.com.au   
      
   On 28/2/2025 11:45 am, 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?   
      
   If you have a definite P0171 DTC, then best you determine why Bank 1 is   
   being deemed too lean. The DTC alone is providing insufficient data -   
   it's a diagnostic starting point, nothing more. An intake system air   
   leak can cause such an issue so look at the intake system carefully for   
   cracked hoses and/or loose hoses or ducting. So can partially blocked   
   injectors. Take a look at LTFT and STFT data. Look at live data, look at   
   freeze frame PIDs. A 20+ year old car is likely to have perished hoses   
   and ducting and can be a PITA to locate when they become the cause of   
   air leaks.   
      
   If you aren't familiar with OBD2 data, consult someone who is. You need   
   to know what data is *normal* and what data is *within spec*   
      
   Dicking with the idle speed *will not fix the issue*. The idle speed is   
   merely a symptom of idle air enleanment, not the cause.   
      
   --   
   Xeno   
      
      
   Nothing astonishes Noddy so much as common sense and plain dealing.   
          (with apologies to Ralph Waldo Emerson)   
      
   --- SoupGate-DOS v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)