Loud banging noise from head but when revved and driven its fine. No loss of power and its suspected to be injectors? Nissan x-trail 2184cc A few months ago I had the switch replaced and reset on the pump and all is fine there, its been a little smokey lately which I suspect was dirty diesel. Fuel treatment (dipetain) is being used and its been less smokey. Sitting at traffic lights last night it just start banging from the top of the engine which inside at the driver seat it feels like a water pump is loose. Any suggestions? Maybe injectors?