After I flush my toilet, right after the tank is done filling but sometimes after a minute (lately it has been directly after) a very loud jackhammer type noise comes from my bathroom. Accompanied by the noise is a vibration that can be felt if you touch the toilet or even the bathroom sink. Recently the duration of this noise/vibration has been longer and it seems like something is just going to explode in my bathroom. I found that leaving the sink on while flushing/after the tank fills it won't happen. Any ideas?

Locate angle stop under your toilet. Close it and Open in All the Way. See if that helps... Back to you... Milo

Thanks, before I try that I meant to add that sometimes the toilet does not flush all the way. All the water from the tank gets drained but it won't have that tight spiral of water going all the way down, leaving some water(and waste) in the toilet. Does that change anything about my problem?

No, that is unrelated problem. Here it looks like you have something lodged inside toilet. You use 5' auger to snake your toilet.

Oh, and is the angle stop the nob under the toilet that feeds water to the tank? If so I just shut it off and then turned it ALL the way open finding that it was originally not open even half of the maximum openness. Does this information help you at all?

Yes, it is the valve that supplies water to toilet... Does it still make noise ?

No it seems to be fine now. Thank you very much I thought my toilet was going to explode. If you don't mind could you elaborate on why this happened. If the valve was the problem why did it only start acting up recently? Could there be an alternate problem? I've been here over a year and never touched the valve.

It was combination of valve being 1/2 way open and its loose internal parts. It should be OK if you leave it open all the way.

Nowadays, we use 1/4-turn ball type angle stops. They are designed differently and do not make that vibrating noise when left partially open...

Glad we solved your problem... Best Regards... Milo

Thanks again!