Okay I have a 99 Ford Explorer XLT, recently got some assistance doing a checkup and decided to pull out a spark plug to see what it looked like. Cleaned Mass Airflow sensor as well. (Got rid of po171&174 error codes by doing so) my father inlaw decided to drive and I rode shotgun. The engine was running like absolute crap at first. Now he lives on an acherage and we hit the rode at highway speeds with it bucking and kicking and there was a god aweful smell to which he thought was the MAF sensor adjusting the fuel air ratio. The engine did not over heat and stayed on average temp. But I noticed the CEL was blinking and to me it indicated the misfire. I hopped out at one point and looked under the suv and seen puffs of smoke+aweful smell of burning or something coming from the upper heat shield on my exhaust. I told him to hit the nearest part store so I could get more spark plugs. Now we drove it at higher speeds and even when it was misfiring he revved the heck out of it saying it did it last time he cleaned the MAF. (Bought it off him) … So we get back, pull the same plug again and noticed a hairline crack in the ceramic. Bingo. Replaced it. Misfire gone and smell eventually dissipated… Now there is a loud metallic ticking noise at idle (possibly at speed) that I never noticed before this.
Any thoughts on what could have been damaged through this ordeal? Should have left good enough alone. What could be damaged by over revving a misfiring engine?!
Read more: Ran Engine with Cracked Spark Plug. Ticking Now?
