I have a 2002 Tracker with the 2.5 L, 94000 miles. I have oil in one (maybe more, haven't checked them all) of the spark plug tubes.It all started with the engine running rough and not idling. CEL code came up as MAF sensor problem. I replaced the MAF sensor and engine runs good but won't idle.No CEL codes come up. I started checking the plugs and found a lot of oil in one spark plug well, didn't check any more after that. I changed these plugs last year and there was no oil present then. I'm going to pull the EGR valve for cleaning and hopefully that will cure the idling problem but how is this oil getting into the spark plug well?