I changed my fuel filter the other day. For the longest time I had code 171 and 1131 which were sensors indicating lean. I disconnected the negative terminal when I did my fuel filter and since then the car's fuel economy seems to be really poor. How long does it take to get itself reset? Also, I did the poor man's kkm that same day and I was so impressed I was driving a bit like a mad man really getting on it. Should I un hook the terminal again and drive a little more normal for awhile to get everything back in order again? Car is 99SE v6 MTX

If you want to reset, just take off the 3 amp fuse (next to the battery) for about 1 minute,
after that your computer will be reseted,
put the fuse again and turn on the car, let it run at idle about 2 minutes, after that drive normally and your computer will "learn" how you drive,
it is important let it 2 minutes idle after reset,

The following is from the Ford TSP (Technical Service Publication):

Resetting KAM (Keep Alive Memory)

Disconnect the negative lead from the battery for a minimum of 5 minutes. Resetting KAM will clear learned values the PCM has stored for adaptive systems such as idle and fuel.

After KAM has been reset, the vehicle may exhibit certain driveability concerns. It will be necessary to drive the vehicle to allow the PCM to relearn values for optimum driveability and performance.


How to Clear Keep Alive Memory (KAM)

The PCM stores information about vehicle operating conditions and uses this information to compensate for component tolerances. When an emission related component is replaced, Keep Alive Memory (KAM) may have to be cleared to erase the information stored by the PCM from the original component.

To clear KAM: Disconnect the negative side of the battery for a minimum of five minutes.