Ball Joint/Front Suspension problems at about 20,000 miles, replaced under standard 36,000 mile warranty.
Fuel pump radio frequency interference problems, ongoing (more below).
Timing chain tensioner, replaced under Ford Campaign (hidden recall) program, at 67,000 miles.
Front timing chain replacement, at my expense, at 67,000 miles, likely directly related to the faulty timing chain tensioner.
The rear wiper almost never returns properly, frequently trapping the blade under the rear upper glass when closed.
The rear wiper blade tension is weak, meaning that most of the rear window is never cleaned.
First, a complaint or two about comfort:
As a tall (6' 1") driver, I find it difficult to adjust the driver's seat properly. It is at the end of its travel, both rearward, and downward. The front bolster is so thick that even in this position, it cuts off the blood in my legs when driving.
My wife is large enough to need the seat belt extender (why do the car companies put such short belts in their cars?), but the passenger side seat belt has an annoying habit of locking at the full out position (this is for locking child seats properly) and every time the Explorer goes over a bump, it tightens. After a while, she has to undo the belt, fully retract it to get it to unlock, and redo the belt. This is annoying, uncomfortable, and of course, a dangerous maneuver at highway speeds.
Now, on to the fuel pump radio noise problem. If you like to listen to distant AM stations, you are simply out of luck, with just about any model Ford since about 1990, when they started putting in-tank fuel pumps in their vehicles. There have been several technical service bulletins put out on this issue over the years (the fuel pump noise is described as "a whining or buzzing noise, coming from the vehicle speakers"), suggesting the dealer install a Radio Frequency Interference (RFI) filter kit on the fuel pump power leads (necessitating dropping the tank and removing the pump assembly -- not for the shade-tree mechanic). If the vehicle is still under warranty, Ford will attempt the fix, otherwise, it will cost you, in spite of the fact that this isn't really a warranty issue (it's a defective fuel pump design -- they left out parts that would prevent the interference, figuring that few, if any, folks would complain).
After getting the RFI filter installed (and to the dealer's credit, they agreed to do it for a $100 deductible, even after the warranty had expired), I find that there is essentially no improvement in the situation. In my opinion, the RFI filter used is a "once size fits all" solution, and more than likely isn't really tuned to exact application, here. To be really effective, the components (chokes and capacitors) need to be directly mounted on the pump terminals (inside the pump would be even better, and should have been the original design), not in some module with several inch long leads. It may be correct circuitry-wise, but it is not doing much good at radio frequencies. The noise has dropped some on the 80 meter (3.4 - 4.0 MHz) band, but it now seems even worse on other, higher frequencies.
Now, most folks would shrug this off. However, as a licensed Amateur (Ham) Radio operator for over 30 years, and having installed and used shortwave transceivers in a variety of vehicles, I've never encountered such bad interference from a vehicle system. The noise from the fuel pump completely blankets most of the shortwave bands, making all but the loudest signals inaudible.
When I initially contacted Ford customer service on their 1-800 line, the representative spent several days "researching" my problem, and ultimately told me that Ford had determined that the technical service bulletin in question did not cover my Explorer (which was incorrect -- I've since obtained a copy of the bulletin from my dealer, and it most certainly covers my vehicle, along with about two dozen other Ford models, dating back to 1990).
Aside from the recent timing chain related problems, the only real beef I've had with this vehicle has been the radio noise problems. Unfortunately, as a federally licensed station officially recognized by the Office of Homeland Security as a first responder, it has been a great source of frustration, and will ultimately more than likely cause me to prematurely trade in this vehicle, in an effort to find one that is comparable, but lacks the infamous Ford fuel pump noise problems. Even though Ford has a complete body bonding (ground straps) and RFI suppression kit, it must be factory installed, and can only be put on police interceptors (since they get loaded up with radios).