I have a 1.8 duratec Petrol engine in a 59 plate focus. When i have the engine running i can hear a knocking/ticking sound and when i place my fingers on the coil packs going left to right number 1, 2, 4 are fine I get a small vibration feeling from these packs but number 3 I get a knocking feeling. I have had no loss of performance in the engine and it picks up very nicely, but when the engine is idling and i increase the revs there’s this knocking/ticking coming from this coil pack.
I have tried to see if the spark plug is loose but this is not the case and tried the nuts and bolts around to see the same but came to the same conclusion.
This is not only an irritating noise but i just hope its nothing too serious
Please can you help with a diagnosis and even a solution to my issue