There has been quite a lot on this problem in the archives.
I have sorted a few, both OHVs and Zetecs.
A temporary "fix" is to reset adaptations by removing power from the ECU - I did the last one by disconnecting the battery for a few minutes.
There is also a keep-alive power supply on some models through a 3amp blade fuse in the fusebox on the bulkhead under the bonnet,and the fuse can be removed for a moment.
TPS replacement can cure the faulty high voltage reading. Anothe member said that he files the TPS fixing holes so that it can be adjusted to rerst the closed throttle voltage to 0.7 volts.