[Dan in Pasadena]

I have an '02 Dodge Ram Quadcab 4x4 which has suddenly shown the check engine light but is running fine*. The * is that I noticed a slight stumble at idle yesterday but it cleared right up and has not returned. This truck has the little 4.7 V8; and though a gas guzzler has been ultra reliable for me.
Truck has 72,xxx miles.

I am wondering about purchasing a plug-in analyzer...which got me thinking. DO I even HAVE OBD-II on this truck? I assume so.

Are the kinds of analyzers you can buy for $100-$200 at the local Pep Boys,Autozone, etc worth a damn? Do they give accurate information? Are they specific as to the information they provide or still leave you to do much diagnosis?

I suppose I should know some of this stuff, but my mechanic training dates to long before on board diagnostic systems.

A link to a thread discussing this or a website would be appreciated too.