Sputtering idle and speedo lights flicker
 

Ok guys, this is driving me insane. I just had my engine rebuilt and now it runs great, except when i get to a complete stop the truck starts idling a little rough, not like its gonna shut off but it sputters and ive noticed that when it does that the lights on the dash/speedo flicker with the rough idle. I have new plugs and coils, i will be replacing all the coil connectors cuz all the clips where broken. Could this be related to my issue? Im almost sure its electrical. Had alternator tested and checked out fine. What else should I look for? Thanks!