1999 gmc savana, gas pedal sticks, when you give it gas its basically all or nothing

A bad engine or motor mount will cause this problem.. The way it happens is, a broken mount (drivers side) will let the motor lift up, pulling the gas pedal wide open, so the motor is probably lifting up when you give it gas letting this happen(in that case you need a new mount)

Sometimes gunk from the EGR valve gasses will build up around and on the backside of the throttle plate and cause it to stick when you are trying to ease the throttle open from an idle. A common symptom is that as you begin to push on the throttle nothing will move then as you apply more foot pressure the throttle will suddenly sort of snap open but will work normally until you remove your foot from the throttle again and the thottle plate closes fully. Thoroughly cleaning the throttle plate and bore will remove the crud and things should work smoothly again. Hope this helps and good luck!

CHECK THE THROTTLE CABLE IT DANGEROUS TO DRIVE THAT WAY