[fuzzypuppy]

I noticed that the engine in your truck was replaced, and not by you, I would say someone stuck a stiffer spring on it, you can streach the spring on there now or buy the proper replacment one from a parts store, you just need to make sure that the "butterflies" (located at the bottom of your throttle body as you look down into it), the thin circular metal pieces that are operated by your cable and linkage are held closed by the spring tension.
I used to run very stiff return throttle springs to stop my "jitter foot" from causing me to red light and for staging at the track when I used to race.
As long as the spring is strong enough to keep the throttle closed when your foot is off the pedal and that the spring is secure and you'll be fine, really it doesn't take to much for this.
One thing for sure if it is that stiff it's not stock or good for your throttle body, it should take no more than light moderate pressure to push the pedal any more would cause the driver to fatigue and that is never good.
good luck.