I have a 95 Explorer with about 90,000 easy miles on it. Today all three rivets that hold the accelerator pedal mounting bracket to the firewall gave way. The rivets all pulled through the firewall, leaving three fairly clean holes. The fix is pretty easy, just drill out the rivets remaining in the bracket, and use machine screws to re-attach it to the firewall. Fortunately, the engine side of the firewall is accessible where the rivets are.
I was kind of surprised to see this failure since I have seen no evidence of much rust anywhere else. So, if your accelerator doesn't give you all the power you expect, you might check to see if the pedal bracket is properly mounted.
Dave