misfire

hi, i seem 2 be having a problem with my 89' e30 bmw 325i, the car is only firing on 3 cylinders(2, 4 & 6), while the other 3(1, 3 & 5) aren't firing. car has constant spark, i even put in a new coil, then i thought it was the cylinder head, so i took out the head, had it completely overhauled, after re-assembling it, the car is exactly the same, i then took of the intake manifold, thinking maybe the injectors were blocked, which they all spray fine when i put directed power on them, lastly i thought maybe its my comp box, i replaced that n still the problem exists. i really don't know what else could be the problem, i would really appreciate it if i could get some help with this problem