Hi, my car has recently had the cams taken out and refitted, since the cams have been refitted the car had lost a lot of power and keeps pinking now and again, anyway, ive found out that the car is only running on the two middle cylinders, i can take the leads off cylinders 1 and 4 and theres no change in engine sound/power whatsoever, ive had the spark plugs out on cylinders 1 and 4 and there both sparking?, do you have to time the distributor up? Please help!. Thankyou