1987 Toyota 4X4 truck

I have a 1987 toyota 4 wheel drive pickup. It has a a 22r engine with a 2 barrel carb and a 5 speed. It seems to run well the first time I drive it each day. The second time however it stumbles, backfires thru the carb and misfires hard enough to bark the tires. I have replaced the plugs and the distributor cap and rotor. I looked for a fuel filter but can't find one or anywhere that looks like there ever was one. Any new ideas will be appreciated.
Travis :(