engine is leaning out when warming up

1999 MITSUBISHI MONTERO
121,000 MILES
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TZIOLA
  • MEMBER
  • 1 POST
99 montero sport w/3.0. Car runs fine until it reaches 151 degrees, then it will barely run at all, unless you unplug the mass airflow sensor(MAF). Battery was replaced and hooked up backwards which is what started this mess. Any ideas would be appreciate When it starts running bad, it leans out according to the oxygen sensor readings and fuel trim.
Nov 1, 2011 at 9:46 PM
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HMAC300
  • ✓ASE Certified Mechanic
  • 48,601 POSTS
  • ASE Certified Mechanic
check for low fuel pressure, and vacuum leaks. scan engine as well and check vacuum at idle.
Nov 1, 2011 at 10:49 PM
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