Ltft
 

Are the Long Term Fuel Trim values stored in NVRAM or KAM?

niether.... you can clear them both and it won't go away....

KAM. However, they are set immediately after the first warm-up to values based on the current drive-cycle.
They don't go away because they are always in flux. As more drive cycles go by, they average and won't move as much unless something drastic happens (like a lot more fuel added or a sever knock event).

Thanks Jeff

Mine are up to 7.2% right now. I have not tried resetting the PCM in awhile. How about removing the negative cable from the battery and pressing the brakes a few times to discharge the remaining charge, will this clear them?

That produces funny results sometimes. The PCM seems to hold onto its power for a long time after it is disconnected from the battery.
Best bet is to leave it disconnected for about 1/2 hour and then still do the full KAM reset manually afterward.