My toilet is constantly running, the bowl water level too high or low and sometimes it sounds like it is flushing. How do I solve this toilet problem?

If water is draining from the tank into the bowl when not in use or the water level in the bowl is higher than normal, the issue is likely your flush valve. Another symptom of flush valve problems is ghost flushing, which means the water level in your toilet spontaneously reduces and then fills up again without pressing the toilet handle. You need to replace the flush valve.