It's inconsistent. Sometimes everything is fine, sometimes after a flush the tank doesn't refill at all at first, then after a few minutes starts to refill slowly, Sometimes the bowl refills with plenty of water, sometimes just a little. It's not leaking or running. Is this a fill valve issue, and would I solve the problem by replacing it?

Thanks much!

It's inconsistent. Sometimes everything is fine, sometimes after a flush the tank doesn't refill at all at first, then after a few minutes starts to refill slowly, Sometimes the bowl refills with plenty of water, sometimes just a little. It's not leaking or running. Is this a fill valve issue, and would I solve the problem by replacing it?

Thanks much!

Tell us which ballcock you have. (see imges) Regards, Tom

It's the first one.

Sounds like you have a faulty seal. Purchase a FluidMaster#242 replacement seal. Shut the water off to the tank and twist the top off the ballcock,(see images) Pry the old seal out and replace it. Work better now? Tom