Cylinder 6 keeps misfiring
Hi everyone. I need your help
After replacing a Leakey antifreeze reservoir with a week or two my 740i e38 started to misfire on cylinder 6 I went ahead and changed the spark plug and misfiring stopped so I changed the other spark plugs too a month later the same cylinder started to misfire again going on and off and ended to be off line most of the time , please help. Thank you.