P1151 Code

Discussion in '1996 - 2004 SN95 Mustang -General/Talk-' started by floridaboy, Dec 15, 2011.

  1. Does anyone have experience with the P1151 code? It's "Lack of HO2S- 21 Switch, Sensor Indicates Lean" I tried swapping the upstream sensors from left-right to see if it was just the sensor but after clearing the code it popped back up again. What could cause a vacuum leak on the drivers side only? I would think that if it was a vacuum leak before the intake manifold both side would read lean. Also it has a pretty erratic idle most of the time. Thanks in advance.