Toilet Bowl Water Level Alternates Level and Flush

[leichte]

My toilet bowl is starting to alternate water levels of about an inch below and an inch over normal bowl levels. When the level is low the toilet doesn't flush all the way. When it's high is does. I've adjusted flapper chain but still not working. This has been driving me crazy. Should I just replace all the guts in my tank?

Any thoughts?

Thanks!

[Jerome2877]

It could be the tube that goes from the fill valve to the overflow tube, this fills the bowl as it fills your tank.

[jadnashua]

A bowl only has one 'right' level. If the drain pipe is not clogged, it can never go higher than the 'right' level (which is determined by the weir in the construction). If the fill valve is not working properly, or was replaced with a generic version, the refill after a flush may not be filling the bowl properly. A generic version fill valve MIGHT not have the balance between water to the bowl and water to the tank correct, and the tank refills before the bowl is full. Often, it's the other way around, but then that wastes water - it just goes over the weir and down the drain.

[Redwood]

Did you recently change the flapper just before this started happening?

Installing a 1.6 GPF flapper on a 3.5 GPF toilet will cause the water level to alternate....
Usually with a good flush every other flush as well.