no idea BOP but u have my sympathy, ya truck looked a great buy but the fucker has played up bad on ya
Can you borrow another TPS from someone? your symptom has the perfect description for this.
ECU temperature switch, 99%. Ask Green Jeep, it sorted his out after suffering the same symptoms.
I'll have another look for this switch later, tested the coolant temperature sensor yesterday and that checked out ok, does anybody know what sort of resistance/how to check the mat sensor as well? I'm just working my way through all the sensors at the moment with the volt meter to try and find whats going on!