This toilet is on a septic system on the first story. For several years this thing has failed to flush maybe 1 out of 10 or 15 times. A plunger easily makes it clear. The shower and sink in the bathroom drain perfectly and are on the same septic system. I have tried using a toilet awl with no improvement. I've also tried vinegar as an acid cleanout and that hasn't worked. I guess it has to be a poor design in the toilet itself. Any ideas on how to fix this situation?
Thanks for any relevant answers.