hey, im only 15 and i am still really learning about cars. i have an 87 z28 with a pretty much stock 305. when i fire the car up it idles really high at about 2000 or more rpm for a long time and then i have to slam the throttle to bring it down, it takes alot of slams to get it to normal idle. i only usually take it out of thegarage and let it idle for like 2 mins and it idels ok after i have it at the good idle speed. but the guy i got it from said when he took the car out for about an hour drive it would end up stalling. i dident really worry about that and it went out of my mind for the2 months ive had it now. so a couple days ago i gotta day liscence on it to take it to get the stereo put in, and after about 20 minz of driving, when we hit a stop light it would just barely stay alive and would juuuust about stall so my dad would have to put it in neutral and just keep reving it when we were stoped. and i couldent see it idleing at all after about an hour of drivving. then my uncle came over who knows a bit more about cars and he played around with the carb(carter afb competition series 4barrel). There was this little mechanism on the left side of the carb with aspring attached,he would fool around with and it only moved about 1 cm back and forth, he said it was part of the choke. and when he moved it around it would idel normally then go back to just about stalling. so if any1 took the time to read this and they have any idea whats wrong, or what i need to do, then please reply, thanks ( and by the way, when my uncle was fooling around with the carb, that was after i had driven it for 20 minz, therfore the problem was present)

THANKS.

 

FYI...when you post a question, do it in one place only so that numerous responses aren't spread all over. Here's mine.....again:
Sounds like you have a couple of things going on. First, make sure the choke butterfly is opening fully after the engine is hot. I have a feeling it's not opening all the way, which is why it's touchy to slow the idle when you hit the gas pedal. If it's closed some, adjust the choke by loosening the three screws holding the black choke housing, turn it till the choke opens fully, and tighten the screws. Your fast idle is too fast also. There is a fast idle set screwon the driver's side of the carb (not choke side) that you want to back out (counter-clockwise) which will slow the idle down some while the choke is closed. After the choke opens, your fast idle cam will drop out of the way of the linkage and the accelerator arm will rest on your main idle screw. Since you have too low of an idle after it warms up, you want to crank in your idle screw until you get your desired rpm's. You'll see the idle screw right in the front of the driver's side of the carb. There are also two idle mixture screws in the base of the carb. What I've described here has nothing to do with those, and you shouldn't be messing with those until you learn how to tune a carb. If you were messing with those, a good rule of thumb starting point would be to screw them all the way in (don't horse them), then back them out 1.5 turns. That'll get you very close to where they want to be.