i think my carb is screwed. i have a 86 w/ the 300. we just got a rebuilt carb not too long ago. ive been having trouble with it sputtering and stalling mostly right when it starts up and shortly after about 10 min. also, the valve that you can see when you take the air cleaner off is like stuck open. it seems like some linkage broke because it moves very easy but it just flops around if you know what i mean. it doesn't spring back when you move it or whatever. its wide open and now my truck is idling really fast and wasting a lot of gas. also, sometimes after i turn it off, when im trying to start it back up again the valve is stuck shut and it wont start so i have to stick something down it to keep it open then it starts but barely. also it's been backfiring like once a day and it never used to. do i need a new carb or what?