Resetting Long Term Fuel Trims
WARNING: This page does not describe the selected car, but rather 25 other vehicles, including the 2002 Lincoln Town Car, 2002 Lincoln Navigator, 2002 Lincoln LS, 2002 Lincoln Continental, and 2002 Lincoln Blackwood. However, it is still accessible from the selected car via links, so may be relevant.
Long term fuel trim corrections can be reset by resetting PCM Keep Alive Memory (KAM). See KEEP ALIVE RANDOM ACCESS MEMORY RESET PROCEDURE under CLEARING CODES under SELF-DIAGNOSTIC SYSTEM. After making a fuel system repair, KAM must be reset. For example, if dirty/plugged injectors cause engine to run lean and generate rich long term corrections, replacing injectors and not resetting KAM will now make engine run very rich. The rich correction will eventually be "Learned Out" during closed loop operation, but vehicle may have poor driveability and have high CO emissions while it is learning.