I own a Chevy c10 swb with a carbed 305 v8. It had been sitting up for a while when i bought it. On the drive home i noticed it start cutting out when it warmed up general around 2000 rpm in third gear (three speed trans) it gets increasingly worse the more you drive it. If you pull over and turn it off for a minute and start it back up it will drive fine for a few minutes then start acting up again. It also has a quadrajet carb on it. Any ideas?