Check and see what TYPE of plugs he installed as well. The dodge electronics are not always friendly with the rare-earth plugs...... if it came stock with copper plugs, and you have iridium or platinum plugs in there, may wanna change 'em just on general principles.

 

^ good advice.

2 years ago I helped a friend with a misfire problem. His dad had changed the plugs, so that couldn't be it. After doing a ton of troubleshooting he decided to pull the plugs for a compression test.

Turns out dad cracked a couple of the spark plug insulators when installing.

 

Life has been hectic and haven't gotten the truck in the garage, yet, but I got some more history from my dad. For the record, I did not pay anything for this truck. He just gave it to me, so I'm not complaining.

My dad was getting the P0303 code. He replaced all the spark plugs and all the coils. He got the coils from AutoZone. He got the P0303 code again. He took that coil back to AZ for a replacement. He got the code again. He took it back to AZ. He got the code again. He bought a set of coils from somewhere else (I think Advance Auto Parts). He and my mom got new cars, so he then gave the truck to me.

My dad is a very smart man, so I'm not sure how he couldn't see that there is a problem with the #3 cylinder. He told me that he just figured the Auto Zone coils were junk.

Like I said, I haven't had it in the garage, yet, so I haven't tested anything.