i have a 1984 k5 with the quadra-jet carb. for the past three mornings , the choke is not opening up after warm-up. i have gone in and flipped the linkage myself to open it so i can go. this morning , no matter if i flipped it ,it would close again. the wire is hooked up and i its not all gummed up on the linkage , actually i think the carb is only a couple years old. is the problem in the choke , or is it in the thing (whatever its called ) that opens up the butterfly ? should i mess with it , or just hook up a manual choke cable ?