front brakes on 93 making weird sounds

[wpatters1229]

I have slotted rotors and ceramic pads...worked fine and then I replaced the pads and now every so often the left front brakes will make a loud sound as if the pads are rubbing againest something and it sounds like a grinding. You can also feel it. I can sometimes get it to stop if I tap the brake or other times it just finally stops on it's own. I looked at the brakes very closely and the only thing I noticed is that there are small slots on the frame where the ends of the pads ride. They look like they are worn into the metal but don't seem to be preventing the pads from moving.
Do these sounds and symptoms indicate a sticking caliper? If so is it better to replace the whole caliper or rebuild it. I have done a rebuild on a dodge van yrs ago and replaced plastic valve bodies with metal and it was great.
Any opinions?