i'm havin trouble

my 86 2.9 bronco 2 will hit 30 km/h and start spiting and sputtering and it goes crazy anyone have the answer?

Check/replace plugs and wires, then? Timing, air intake.

Check/replace plugs and wires, then? Timing, air intake. i did that and still the same:banghead: some people say that the oxygen sensor might be it ?

Did you change your fuel filter? If you tuned it up are you getting any codes.
Also check your air filter. I have found many people use cheap plug wires and I have had to remove the wires and recrimp the ends normally the plug end.
I have noticed some auto zone and advanced employees say not to gap the plugs which isn't correct.