Check Engine Light

Hi everyone, I have a check engine light in my 93 t100, and it is idling a little high since it came on. about 1500 instead of 900. I am going to check the vacuum hoses for disconnects, but any ideas? and more importantly, how do you read the code from the ecu? I heard you could jump a wire and read the code, kind of like a honda? any help would be useful. Also,
we don't an Autozone nearby, so I can't just drop by there :)
Thanks,
Matt

On the underhood diagnostic port connect a jumper between TE1 or TE2 and E1 and turn the key on. (Do not start the engine!!!) watch the check engine light and count the flashes.
http://i43.photobucket.com/albums/e362/bindertch/t100.jpg