obd2 interpretations

Is there a site besides alldata that can help in diagnosing the trouble codes obd2 scan tools display?
For do it yourselfers it would be nice.
I have a 96 Windstar 3.8 that keeps coming up with p0304 (misfire #4 cylinder) and p0340 ( camshaft position sensor). Sometimes the #1 cylinder comes up with the camshaft position sensor. Once and a while the obd2 readout has multiple cylinders (p0300) come up.
I replaced the plugs and wires, the egr valve,and I replaced the camshaft position sensor 5 times. It still comes up with the same numbers. No noises.
The engine misfires through most all of the driving ranges infrequently when I am on the highway as well as in town driving.

Is there a site that might have what the normal range of readouts should be on the obd2 when observing the obd2 recording areas?
Having trouble diagnosing.
Thanks for any help!!!
Johnny

if you go to the Autozone website, and register your info you can get the actual read out of all the code pertaining to your vehicle. This is whee I got my codes and it helped me. Or you can hit up google for the codes and a multiple websites willcome up. hope this helps