you could try swapping the stalk out for another one, it's been a while but from memory there's a couple of bits of plastic on the end of the stalk; one for left one for right. when the wheel turns part of it catches on whichever bit of plastic is sticking out (depends on which way the indicator has been pressed. this little plastic bit is probably worn out on yours. new stalks aren't that expensive and while you're at it i think you can upgrade to a later model (vt??) item which i've heard look better but never checked.
yea you can get a VT one as i have one in my VP, just make sure the VT indicator stalk doesn't have the cruise control buttons. Do you have an aftermarket steering wheel? as that may also be the problem is the boss kit isn't lined up properly.