Debs10 Trouble

Can anyone help me. My 1986s10 2.8 4x4 Has still got problems. we have done every thing to it. put every sensr it has go on it new fuel pump new comp. new timing chain an gears. new injectors an it still idles up an down about 2-3 minutes after you start it. it want take the gas at first then it will. when you let off it backfires really loud like it is to rich on gas. does anyone no what it may be? Thanks DEB

didja replace the MAF? Is ur disrtibutor set correctly? make sure your plugs are in firing order and clean.

I agree with GirlBear on making sure the distributor is set correctly, Also how good is the Disty Cap, Rotor, Wires?