Brake Problems
 

I've got a 99 tacoma prerunner. I've changed the brake pads on it a couple of times (the last time about 6 months ago). Now for some reason, every once in a while the break pedal seems really stiff. It brakes fine but the pedal barely moves. I don't have to depress hardly at all. Then it'll work fine for the next couple days or so, then it'll happen again. I'm also having a difficult time shifting it out of park (it's automatic). Almost like it's not registering that the brake is pressed. I'll keep pressing the brake pedal and trying the shifter until all of a sudden it'll work. Could I have air in my lines? The fluid reservoir is full, so no problems there. Any ideas?