Yes, more details are needed.
Most coaches have 12v lights. When you are plugged into shore power a converter changes the 120 VAC to 12 VDC. Sometimes it also charges the 12 V battery, and in other cases there is a separate battery charger. Either way, though, most of your lights are operating on 12 VDC.
You can start at either end of the chain. One end is the shore power pedestal and the other end is the bulb. The more lights that flicker the more likely the problem is closer to the power pedestal.
Briefly, you are getting power from the pedestal which travels through the cord to your coach. Inside the coach that power is changed to 12 VDC which travels through smaller wires to the various switches and then to the lights. Fuses or circuit breakers protect the several circuits.
I think I'd start with your plug. Turn off the breaker in the power pedestal, unplug your cord, and wiggle each of the four metal prongs. If any of them seem at all loose, take that end of the cord apart and tighten things up. If all are tight, move on to where the cord attaches to the coach. Many coaches have a ring that tightens the cord to the connector. If yours has one, make sure that it is making a secure connection. See if the cord wiggles after the ring is tight. If it does, you may have found your problem. If not, the problem may be either inside your coach or in the power pedestal. Either way you may want the services of an electrician.
If you are comfortable with continuing your troubleshooting, though, see if you can get to the back side of where your power enters your coach. There will be four wires that attach there. Make sure that all four are tightly attached to the terminals. The other end of those wires will be in your breaker panel. Again, check every connection.
Then on to the converter/charger. Make sure that all connections are tight. Also check the battery connections.
My bet is that you have a loose connection on your cord OR in the power pedestal.
Mercury Mountaineer towing mpg 181(both sold)
1993 Foretravel U300 40'