Idle Problems

[DOLLARS_AND_SENSE]

Today some friend and I were sitting in an empty parking doing nothing and so I decided to spin my tires a little bit just for the hell of it. ( Something I have done several times without any problems.) After I had spun the car once or twice I parked it, but before I could turn off the key the rpms jumps to about 3000 and stayed there. I thought maybe I need to let the car cool down but that did not help, so now whenever I start the car it idles at 3000 So in between shifts the engine is revving like my foot is still on the gas!!I checked to throttle linkage to see if sticking open but it appears to be in the closed position. I really don't know what else to check. Is there an idle ajuster? If so where is it? (Oh yeah it is a 1991 240sx stock) Has any ever had this problem? What causes it? How can I make sure it doesn't happen again? I just changed my air filter and installed some speakers if you think has something to do with it. Any help would be great!! Thanks!!

[solaris22]

stop screw should be on the throttlebody.

[Structure240sx]

did u take off the intake pipe to make sure the throttle plate is closed when it should be? and the idle adjusting screw is on the side of the intake manifold at the 4th runner where the lower and uppser half meet, around there at least