Nissan Repair: 1996 Nissan truck, nissan truck, gas sensor

Question
It began missing and idling really rough and I changed the spark plugs and upon changing them, I noticed a rich gas smell on the plugs.  More than normal.  My guess is that there is too much fuel being delivered but I am not for sure.  Any suggestions?  Thank you for your time.

Answer
Rev Gregory,

I would also change your Distributor Cap & Rotor (for you miss) but running to rich I believe it could be your Exhaust Gas Sensor.

You will have to test this Exhaust Gas Sensor, so please refer to your Manual for the "Specs" on how to test this part.  
Make sure your "plugs" are gapped to the manufactures specs, for this could also cause you to run to rich.

Hope it starts purring again nicely for you.