Idle problems

[Idle problems]

Will go out to start the car and it will go up like it wants to run then immediately drop below 500 rpm killing the engine, Restarting car with gas pressed a little will be a bump a little and smooth out, in order to drive you cant let idle drop to low, upon stoping completely and taking off its studders from 1000 rpm to 1200rpm, at 1200 rpms it wont stutter after stoping (it wont stay above 700 unless gas is pressed ) NA 91 no engine light and was working fine the other day, It seems to change weekly from really high idle (40mph) to a fluxuating out of gear idle to a very low idle. also normal idle days after going 80+ for extended period upon reaching a exit ramp the idle will drop and car will die and you have to hold gas abit down to go


Any ideas?