88 dodge ram 100 idle problem

1988 dodge ram 100 4x4 318 fuel injected, when i start this truck no matter if the engine is warmed up or cold it idles up REAL fast like 2000 rpms or so, i turn the adjustment on the kicker motor all the way down, but it still rev's way up. is this normal on these truck ? i just don't see why it should idle up so high when the engine is already warmed up. this engine has allot of miles on it I'm sure it cant be good for it to rev so high as soon as it starts.

if anyone has an idea how to fix this or if it is normal id appreciate your opinions, thanks in advance