Well lets see Ford bad engine designs:
1) The early 5.4 blowing the spark plugs out of the heads. Many need to have the complete cylinder heads replaced because of this issue.
2) The 4.0 V-6 timing chain guides that wear out at about 75 K and drop metal shaving into your oil pan/pump. Many start to knock at 80-90K.
3) The Infamous 6.0 diesel. Ford admits it spent over one billion dollars in warranty issues on this boat anchor of a motor.
4) The 6.4 diesel With EGR cooler problems,head gaskets, timing gear covers eat away with coolant. Plus many other coolant related issues.