code p171 bank 1 too lean. what should i do to fix it?
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1999 Ford F-150 Question: check engine light on
Answer #1Hightec1 February 26, 2012, 21:24Technician
The 2 things i would do first is have someone check for vacuum leaks
with a smoke machine.
And also have the MAP sensor cleaned.
Reset the engine light and test drive it.
Sometime a collapsed vacuum hose will not show up with a smoke machine
because the smoke pushes pressure in the hose.
Have someone check all hose with a good bright flash or drop light.