Code P0108 2000 Jeep Grand Cherokee Limited 4.7 liter V8

Hi! I have a 2000 Jeep Grand
Cherokee Limited 4WD with the 4.7
liter V8. Just a few days ago I was
driving down the interstate going
about 75 mph when my jeep jerked
really bad and the check engine light
appeared. I've been driving for about
a week since this occurred and if the
car sits overnight when I start it the
next morning the check engine light
will be off. The car runs perfect when
the light is off but you always know
when it comes on because you can
feel a difference. It tends to come on
when driving in town (stop and go) or
at high speeds (on the highway). And
it will have a tough time accelerating
at first (1st and 2nd gear) then it's
fine. I did the little turn the key on/off
3 times thingy to get a code. And the
code shows P0108. Anyone know
what this code means and how to fix
it? Anybody else have this problem?
Your answers are appreciated!