No sensors, no internal problems. Here's the quickest fix you'll ever do!
As your truck gains age, the throttle cable stretches. This stretching causes slack at the throttle pedal and leaves a "dead spot" just like you have described.
Take a Zip-tie and cram your head up under the dashboard so you can see the TOP of the throttle pedal. You'll see the throttle cable coming through, with a plastic stopper at the end retaining the spring.
Pull the throttle cable towards you (away from the firewall) so that all the slack is out. Now place the Zip-Tie on the cable to keep the slack out.
This will slightly tension the cable so it provides better and faster throttle response!
If you'd like more info, do a search on "Throttle Cable Mod", or just reply on here and I'll see what I can do.
The Black Beast 5.0
Better to Have Horsepower and not Need it, than to Need it and not Have it!
2000 Ranger Sport - 5.0L V8 - 8.8 LS rear