check engine light on on 1999 Ford F-150

code p171 bank 1 too lean. what should i do to fix it?

Asked by for the 1999 Ford F-150
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.