If it is coming from the tub spout then the gasket is moving around or esle it is shot. The easiest way to fix this is to get a new tub spout. It will more than likely take more time to attempt to change the gasket on the spout then to install a new one.
It doesn't but you better run sir/madam their may be a ghost in your bathroom.
turn on the heat
More "VOLUME" flowing from the tub spout then the shower head as the shower head has a flow restrictor
Often a faucet will sputter if there is air in the lines. This happens if the water has been turned off and then on again. If this is the cause, it is only necessary to run the water a while and the air will get out of the lines, and the sputtering will stop.
it is run off of a different line from the main water supply. you may be able to trace it from the hot water tank and see where it branches off.
They both run
The tub spout diverter,is just worn out.Go to your plumbing or hardware store and buy another with the same installation properties.(You may want to remove the old one to see how it was installed)
One of the things you do after a run is a post run warm down. Other things include drinking water, having a snack, and showering are also things done after a run.
I just installed an American Standard kitchen faucet and it continues to run for a second or two after turning the handle. I called AS and they said it is because of the high arch and the location of the stop valve lower in the fixture. I think it may have more to do with this being a lower end kitchen faucet. During a bathroom remodel we installed a high arch Pegasus bathroom faucet and, while it is admittedly not at high as the kitchen faucet, it stop immediately and doesn't continue to run/drop at all. When I removed the Pegasus faucet filter at the spout, it behaves just like the kitchen faucet, so there's some sort of stop valve element at the spout of the Pegasus that isn't part of the AS faucet.
Defective divertor
Very simple. Run each faucet until there is no more air. This usually only takes a minute or two per faucet. Remember air is lighter than water and will quickly rise, thus exiting the faucet additionally the strong flow of water out of the faucet is a huge plus.
There are several things one can do to reduce pollutants in their household. One being never run a car with the garage closed. Another is opening windows while cooking or showering to get air circulating.