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				Hi. My 172 suddenly developed a really bad miss fire (it sounds like a rough subaru) I changed the spark plugs and this helped quite a bit but  didnt completely cure it however it was much better. Now 2 days later the missfires back as bad as ever along with a flashing eml light it doesnt happen at idle only when revved. What could this be? So far iv considered injector or coilpack could one of these be the culprit?
cheers
			
			cheers