Trouble dying hair

It sounds like you have colour build up, have you been using permanent dyes on it? You need to use a colour remover (judging by the spelling you use for colour I'm guessing you are in the USA? if so you want to get Color Oops which is a colour remover, avoid the other brands that are colour strippers as they are much more damaging!).

Colour removers can be used up to 3 times to remove permanent colours from the hair. Results vary as some dyes can stain the hair shaft and often even colour removers followed by bleach will not shift this! Don't be alarmed if your hair ends up a gingery colour after using the removers either, they can not restore your natural colour so they will take your hair to the shade it has been lightened to by the lightest dye you have used, which unless you have previously gone blonde is often ginger!

After using the colour remover you'll need to rinse your hair for a really long time, then it is not advised that you use a permanent dye for a few days, during which you should thoroughly wash your hair a few times to make sure every trace of the remover is gone, otherwise you risk re-oxidisation meaning your hair will darken again.

You can use direct dyes such as Directions, Adore, Manic Panic etc straight after the remover.

What hair colour is it that you are aiming for at the moment?