More specifically, one or both magnets on the spindle may come unglued and that causes erratic idling.
When you fitted the new TPS, did you use a multimeter to test the resistance on the four contacts. You should aim to adjust the position of the RPS , so it can give you values as close as possible to 0.5KΩ and 2.5 kΩ,
Also, if you are anywhere near East London, you can drop by and I can read the codes of your car with my Vida DiCe foc