Dont bother buying a code reader, you don't need one. I believe the 22res are the same code checking system, so try this first. Next to the engine bay fuse box is a little grey box (diagnostic port) he inside of the lid should have a sticker that labels the ports, so look at that, and install a jumper wire (paper clip works well) between Te1 and E1. Turn on the truck (don't start it) and the check engine light will blink a sequence of times to indicate the code. Look up the code in a chiltons/haynes book, and you'll see what the problem is.
This is the system for the 3.0, like I said before, I believe the 22re diagnostic system is the same, but I'm not positive. A haynes/chilton book will tell you how to check the codes however, and give you the list of codes as well.
