My engine used to jump up to about 3000 RPM's suddenly. this could happen when just starting it up or simply idling. And more dangerously when driving which would not allow me to slow down as much by simply letting off the throttle. Ford garage claimed it was the idle air control vavle, which was replaced twice with no improvment. I later read over the manual enough and found out about the throttle postion sensor (TPS). When i replaced that part the problem was fixed for about 6 months. It seemed like it was starting to act up more when i was at full throttle more often, like climbing the 5 mile road up a mountain or when frequently offroading.

For extra info the TSP is mounted on the bottom of the throttle body and is actaully wired into the idle air control valve by a plastic connetor, the engine is the 5.0l 302 v8. Also the TSP has an adjustable screw on the bottom which has a part in controlling the air-fuel mixture. which also seemed to be a little off after installing the new one i think. it gives off somewhat of a gargling sound hit you hit the gas and let off now. i would highly appreciate some advice with these 2 problems.