Tank fill valve sticks

Is the flapper valve closing sooner then it should? Is the water line (the 1/4" vinyl tube at top of fill valve) going into the tank or into the overflow tube? Did anyone drop anything into the flush valve?

Just replace the whole assembly. It only costs 12-15 dollars. Water contains so many minerals that just clog up lines like cholesterol. Just be done with it. It is not worth the effort to try to clean all that out . Plastic is sometimes not very forgiving.

Replace the assembly. This is common in areas with high mineral content in water. You will be glad you did. Delay too long, you may find your toilet running while you are at work .

http://www.acmehowto.com/howto/homemaintenance/plumbing/toilet/tank-valve.php
This is usually the float valve please see this link above for help...

Make sure the fill tube in the tank from the fill valve is in the overflow tibe inside tank. The tube allows bowl to fill with water to correct level.

Take the tank back off and make sure the tank to bowl gasket is set correctly and the make sure you tighten the bolts down evenly.

Water Level Adjustment
1. To adjust, simply turn upper half of valve counter-clockwise to unlock, pull up till water line on valve is level with water line marked in tank, Fig.C then turn clockwise till valve snaps into locked position.
2. Turn on water supply to fill tank.
3. Tamper proof key is optional, and may be used to simply to prevent further adjustment once final setting is achieved. Fig D

It is most likely that it could still be your flapper. Toto has its own brand of parts made specifically for each of their models of toilets.

If the chain has fallen off the valve just turn off the water inlet and flush, it will not fill now. Put chain back on if the valve area where the chain connects is ripped, replace rubber valve. Turn on inlet and grab a magazine and enjoy your quite time! Happy trails to you :)