Problem : Car In Limp Mode

[julz2bit]

Hi i have a r34 and for some reason it goes into somthing like a limp mode where its only firing on 3 or 4 cylinders , Ive just replaced oxy sensor and plugs and 2 coil pack have been repalced ive cleaned the air flow meter aswell . Could it still be the coil packs ? I so run out of ideas . Because Its happening twice a day on the way to work and then on the way home. I used to be able to restart the car 4 times and it would be ok but now that doesnt help. The only other thing that happens is my slip light comes on and trac control light and the engine light and abs aswell. I went to the auto elec and he pluged his computer in and came up with a error 21 ? dont know what that means . Can somone please help.

[DrewII]

im having same problem with mine too. diagnosing it this friday. its either coil packs or foul/worn spark plug. the same problem used to happen to my previous car it had a cracked cylinder head and it was fouling the spark plugs every 1000 kms they had to be changed. its definetely not a cylinder head iv had my cylinders tested, fuel pump, afm everything. its pretty much come down to coils/spark plugs. will let you know what the problem is this friday.