So there's nearly 200k miles on the truck? smilieFordlogo . Or you didn't buy it new.....and the idle on my truck (2013) doesn't change with the brake lights. You have a gremlin.
Had an Xtang on the 07, and have an Access on the 13. Both roll ups with velcro,and built in support bows. Both functioned flawlessly. Roll ups are the way to go if you use your bed.