There are three major components in the connection from your foot to the throttle plate. They are the gas pedal, the throttle cable and the throttle shaft on the throttle body (TB). You, and only you (or your mechanic), can check each of these components independently for restriction.
At the throttle body, use your hand to rotate the throttle shaft to fully open. Did it rotate freely against the spring pressure? If not, you need to clean the spring and shaft areas with intake or carb cleaner and relubricate the spring and shaft with a light oil or motor oil.
If no resistence in the throttle shaft, with the throttle held fully open with one hand, use the other hand to push and pull the thottle cable. Does it move freely or is there friction? If it does not move easily, you can remove the metal anchor on the end from the throttle shaft plate and the cable from the mounting bracket. The cruise control linkage snaps off the throttle lever. Examine the connector to see which way to gently push to remove it.
With the cable free at the TB, raise it as high as possible and use a lightweight spray lubricant (NOT WD-40) with an extension tip to fit in the rubber boot on the end of the cable. Spray the **** and try to exercise the cable to distribute the **** down the cable. You should do this until the cable moves freely. If you cannot, you may need to completely remove the cable and try again or replace the cable (if you can locate one).
If the cable moved freely, you need to examine the gas pedal and its lever to find if there are any restrictions or interferences to its motion. The pedal has no spring of its own and should move very easily. Remove obstructions and lubricate the pivot point as necessary to free the motion of the pedal.