There are several things to look at, check the hose that goes to the MAP sensor, it's the flat
black box with wires next to the battery, then check the TPS adjustment, but I think you
might just have a problem with either the throttle "kicker" , it's the vacuum controlled thing
on the back side of the TBI unit, and is supposed to open the throttle a little for something
like electrical load or cold start, I'm not sure, I took mine off, then you might just need to turn
the idle screw up a bit to get it idling at about 800-900 RPM.
The kicker on my truck was causing a random high idle situation, so I pitched it, no A/C and it
seems to idle ok with the headlights on so it's not a critical part in my book
Wild