My brake pedal sometimes sticks on my 2003 3.OL OHV V6. This does not happen all the time. I'm usually going about 20-30 mph, apply very slight brake pressure to slow down and notice the pedal sticks. I have to use the top of my foot and pull the pedal towards me. It seems to be becoming more prevailing. Had Pep Boys perfrom brake inspection recently; they gave me an OK, but the problem was not then accuring. Brake Fluid level is OK. I thought it might be a caliper piston sticking but it only does this periodically. Can someone offer any advice on how to throublehoot this further or offer any thoughts? Thanks in advance.