Q: When I give my car gas and let off it keeps throttling up by itself, I changed the tps sensor no help

In the majority of vehicles, engine idle speed is controlled by an idle control valve (ICV). The ICV valve can fail or a faulty or blown fuse in other electronically controlled systems can cause the IAC motor to malfunction, leading to a higher than normal engine speed. Failures in the ICV valve itself are often due to excessive carbon buildup in the intake manifold. Other possible causes of uncommanded high engine speed include vacuum leaks, a malfunctioning throttle and, rarely, a PCM/ECM malfunction. With regard to vacuum leaks, on a fuel injected engine a vacuum leak will cause higher engine speed as the engine’s oxygen sensor detect the extra oxygen entering the engine through the vacuum leak. The newly lean (too much air relative to fuel) status will result in the engine’s computer pumping in additional fuel, resulting in an abnormally high speed. If you desire that this problem be diagnosed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an engine speed diagnostic - high idle/uncommanded high RPM and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.