How Can i tell if my truck is running rich and should i fix it even though its running pretty good?
The best way to tell is to install an o2 sensor and air/fuel gauge. However you can sometimes identify either condition from "reading" the spark plugs. You just wont be able to fine tune it like with a gauge. Either condition should be fixed to make sure the engine runs efficiently and reliably.
if its running rich you should be able to smell gasoline in your exhaust. its not a big deal but if you're bothered by it adjust the carb