you can check the timing pretty easy by pulling the valve cover off, then putting the crank at tdc on number 1 both valves closed in the front and make sure that cam dowl hole is at 12 o clock. If it isnt then it's jumped a tooth.

I suppose it's also possible of a bad ignition componet also.

8 Starion SHP, 87 mitsubishi van, , 81 galant g54bt, 78 lancer g54bt, 1965 Mitsubishi Debonair Deluxe
87 swb montero offroad pkg goin g54bt with sr locker 33x12.5 dual bouncy.