Check things as Pablon2 mentioned..... now you need to understand how the electronic version of the throttle system works.
1. Turn the key on the computer takes a voltage reading of the TPS (throttle position sensor) and for that run that is the base voltage it will use for everything else. Typically this will be around .95 volts. A little less is fine, but much above that you will need to tweak it down. Mechanically, the throttle blade may be just cracked open and no more at idle. During this time, the IAC is controlling the amount of air going into the motor, NOT the throttle blade.
2. Everything else for the throttle being considered at part throttle and WOT is based on reference voltages, which is the voltage setting in the computer plus the idle voltage obtained from 1 to give you the state your looking for.
3. Generally the computer will have a max voltage setting for the car, which I think is around 4.5 Volts total, and may not be the actually fully opened position mechanically... rarely is.
So technically you could still be getting full throttle range. Also if you do tighten up the cable if it is that loose, then don't tighten it right up either.