My 85 S-10 LB PU w/2.8L is overdue for smog here in Ca. When I got it back from long term loan to my daughter, it "bucks" like a bronko in 1st 2nd and 3rd. Runs good while warming up with choke on. I'm looking for a used carb, but in the meantime I would like to troubleshoot to make sure it is not something else. Fuel pump, vac lines etc.