so recently my '88 3.0 has been acting a little weird

it starts up fine, but idles at about 1500-2000, and stays there, (usually it drops down to 700-800 where it should be once its warmed up)

then after you drive for a few minutes and get stopped at a light or something, the idle will surge up to 1500ish, then drop to 1000, and it does this repeatedly and consistently, then after driving for a while, the surges stop but it still idles high 1200-1500.

some of the symptom sound like TPS, but i'm not to sure.

it still runs strong, and has the same amount of power, (or lack of...)

any ideas guys? thanks