Chevrolet Repair: 1989 Chevy S10 Throttle Issue, chevy s10, liter engine

Question
Hello, I recently acquired an 89 Chevy S10 with a 4.3 liter engine and 150k miles.  The freeze plugs were shot and I replaced them.  I just got the car back together and am having a problem with the throttle.  The car starts up fine, but when I press down the throttle, it sticks.  However, this does not happen if I press the throttle when the car is off.  Do you have any ideas of what the problem could be?  

Answer
Hello Aaron,
I would look at the motor mounts to see if the engine is rocking too far, and binding the throttle cable.
I would also operate the throttle lever directly on the engine and see if the cable has anything to do with it or not.
There may be a spring missing that is supposed to return the throttle plate to closed. The incoming air might be holding the plate from closing if the spring isn't connected properly.

Van