2007 Ford Explorer Pros and Cons at TrueDelta: Owner Pros and Cons by jdgdredd10

frequent failures of coil on plug (cop), not the plug itself but the coil which attaches to the plug with one nut usually during wet weather. cheap enough to buy and replace for a simple minded mechanical type person; but you must identify the faulty coil first. take it to most any auto parts store that can ID your code, no charge, then buy the cop and replace it. i initially bought the cop with a lifetime warranty, paying about 3 times the cost of a single cop. however i have recouped that cost b/c i have had at least 4 failures of differing plugs.

also replacing spark plugs are very costly, but fortunately they are good for about 100k miles.