I live in a mobile home and my guest toilet continues to back up. When you flush it the water level will rise to the bowl rim and slowly go back to normal. I have taken the toilet off of the floor and cleaned it out, replaced the wax ring, and cleaned the gas vent that goes to the roof. I have also had the septic pumped as a last resort but it doesnt make any sense that it continues to back up. My other toilet doesnt do it and the guest toilet just started to do it out of the blue. Does anyone have any other ideas?
It sounds like something is in the trap of the toilet. To be positive, you can run a camera through it, or alternatively, remove the toilet and pour a large bucket (larger than a flush) of water down the exposed drain - if it drains quickly and does not backup, you know the issue is with the toilet. If it backs up then you know the issue is with the drain (or vent possibly)
If the drain is the problem then the best bet is to have a plumber come run a camera down it to determine where the problem is (from the question you said you "cleared" it, I assume this means running an snake/auger down it) It could be an object is stuck, or the drain could be collapsed, etc.
If it is the toilet then you need to and remove whatever is stuck in the trap. Sometimes objects like toothbrushes can get really stuck and the only option is to replace the toilet.