A couple of days ago while driving my 91 honda civic si my throttle stuck, and the rpm redlined.I immediately put the car in neutral and turned the key off. Now every time I start the car, the throttle acts as if it is stuck wide open, the rpm gauge maxes out, and it idles full throttle(if i left it running that is). Well I have checked over the throttle body, the throttle cable, and everything looks fine. I have no idea what this could be besides maybe the TPS sensor, or a vacuum hose? I do not know, and desperately need help!

 

Does the gas pedal work normal with the engine off? By that I mean that you can push it down and it springs back up all the way? Return spring on throttle body could be broken. Manually turn the linkage closed, to pull the throttle cable all the way out under the hood. I don't remember if those has cruise control. Cruise control of course works by pulling the throttle open with another cable and it could be stuck.

If throttle plate is closed, brake booster could be blown causing a big air leak. Pinch off the hose to the booster.