sudden misfire on A bank

[blackjaguar]

Need Help
yesterday i had nothing better to do so i decided in removing a spark plug from both sides to check strength of gap. the B bank i held near a bolt and started engine afew seconds spark good.A bank i held sparl on fuel rail/injectors all ok.when i fired engine up a misfire has ocured on A revs down from tick and exhust bad sound also popping when high reved have i damaged coil module ets please help
nick

[BigCatXJS]

Hi,

Please update your profile (or post here) with the year and model derivative of your XJS. That will help folks provide the right advice...

Thanks.