my 2001 silverado starts and run fine gives no codes until on the highway for 10 to 15 minutes . Then I have a complete loss of power but it stays running. It then codes po 171 and 174 left and right bank too lean. No warning or display on dashboard. When it is cold started it runs fine and initially displays no codes and passes all I M monitors. I have just changed my fuel filter my alternator my fuel pressure regulator and the EGR valve . I also cleaned the MAF with MAF cleaner. There is no change. Any help greatly appreciated.
Jul 19, 2008 at 4:58 PM