its a 91 4.3 v6 jimmy. so its been running like crap lately and today it started squeaking from under the hood, i stick my ear close to the throttle and i hear the noise. i take off the air filter and move the throttle by hand. smoke starts coming out and im scared my truck is shot out. my o2 sensors have gone to crap too so it reeks of gas from the air filter so i cant tell if it smells wrong. help me please?