From your other thread, you said this started happening right after you washed the engine off. I'd bet on you getting water into the TPS as this is a common issue and affects the TCU's view of the world. Try replacing the TPS first, it is far cheaper and much more likely to be your culprit. Also follow the instructions from the other thread and use some contact cleaner and dielectric grease to clean out the connectors, ESPECIALLY the TPS connector.