That's all I have to say! Blown Spark plugs! Run! Run! Run Away! Will cost $500 min each plug to fix! This is a major problem! They blow up and out of the hole because there's only 4 little aluminum threads holding them in. Then they hit the fuel rail rupturing it and wah lah your car is a BBQ! Ford ignores. Says nothing's wrong. Great quality!
Umm 500 per spark plug? 4000 for heads work? I doubt that, You can buy some trick flow heads, and have them installed for less than that. and the reason the plugs "blow" is because people over tighten them