Car taking off without touching gas pedal

I have a six cylinder engine my car. It starts, idles fine, no obvious signs that something is wrong. I drive through the city and on and off the gas often, but when I take my foot off the gas, it gradually speeds up. I have to press the brakes hard to turn in any where! I am at wits end, the valve that has a wiring harness on the neck of intake, two bolts and it is still doing the same thing. Any help would be appreciated.