CAR ACCELERATES AT FULL THROTTLE ON KICKDOWN

gas pedal sensor could be faulty or the ecu is telling to to speed up.

The idle air bypass valve or the throttle plate could be gummed up and in need of cleaning.

you either have a plugged fuel filter, a plugged converter or a bad mass air flow sensor

Replace the cable with one from your local auto parts store or dealer.
It may be for cruise control if your cruise control no longer works.
Or, it may be for the accelerator pedal.

turn the heater upto full heat (no a/c)to see if the temp goes down if it does then change thermostat.(i assume the fan(s)work)regarding the car accelerating on its own this is an anti stall feature on most cars(not all)especially VW group,it is also very comfortable in heavy traffic conditions when you dont need gas to move.(put the car in 2nd and crawl along with the rest)

its that throttle body you put on doing it try changing the mass air flow meeter and setting up the throttle pedel poshion switch this may sort you out,,,
if the throttle poshion switch is not set up it throws the gear box into a wobbely

Sounds like a tranny valve body problem.There's a down shift cable attatched to the throttle linkage (where the accelerater cable is).That cable may not be adjusted right.However if you dissconnect the cable from the throttle linkage try to pull the cable out to where it stops(it'll retract by itself).Then let it snap back.(repeat a couple times).This may unstick a vavle in the valve body

This s a throttle response sensor AKA kickdown sensor. and its bad replace it

your torque convrtoer is shot. it is the at the front of the tranny to transfer motion from fly wheel ( engine side) to the trans. its a fairly cheap and easy fix.

This is only a suggestion, if you used the cruise control lately, better have that checked, it might be stuck in the on position