Dakata truck

If it stays too high start by checking the vacuum hoses for a leak. Pinch off various hoses to see if one brings the idle speed back down. You might also suspect a sticking automatic idle speed motor. The Chrysler dealer can use their scanner to run it up and down to see if it is working. The scanner can also be used to read the number of "steps" the Engine Computer is commanding that motor to. Normal is around step 32 for a properly running engine. If you find it is much higher and the engine is running too fast, the computer is commanding it to run faster in response to some incorrect sensor information. If you find it is closer to step 0, the computer sees that idle speed is too high and is trying to bring it down without success. That's where a vacuum leak would be suspect.