post a couple of sample pics here .... easier to visualize
what other settings do you use in the following areas?
exposure metering mode (centre-weight, general/matrix etc etc)
what speed setting are you using
whats the max apature range on the lens ? (or just tell us what lens model you are using...that info is usually printed around the circumfrence of the lens area)
then its easier to understand the situation and analyze and advise
anyway, here's a little reading about using Tv mode (Tv mode DOES NOT mean that your pics come out like television images LOL :bsmilie: )
http://www.learnslr.com/digital-slr-learning-guide/tv-mode-shutter-priority