2002 volvo s40 t4 stutters on acceleration

[r8bwp]

Car started stuttering, engine management light flashed.... decided to call the rac he put diagnostic on and it came up with misfire pot3. he checked the plugs checked the spark checked checked the coil with a neon light checked the fuel injector the fuel injector, he cleared the faults and followed me down the road, the problem persisted( stutter started on hard acceleration and became noticeable at 80mph), he suggested change plugs and then the leads, then the coils.

I have changed the leads and plugs and put a new petrol filter in too.The throttle body has been thoroughly cleaned

If its not the coil I will be at a loss any ideas?