Just got another series2 v6 put in the misses vp had it back afew weeks she went and got the kids from school and i heard her coming up the street it was running that rough and loud.Anyway ive noticed abit of oil in the radiator the car starts and idles well when i rev it it is loud splatting and rough.Also the car played up after the misses put 20bucks of juice in.When i drive it when i put the foot down it does'nt wanna go anywhere.
sound like a few cylinders missing, try testing the spark from the coil packs, i'd say they are dead, also the oil in the radiator is from the integral trans cooler inside the radiator, you'll need to do a system flush on the trans and coolant and replace the radiator.
As was stated it was a coil problem fixed thanks all.