I have a nissan titan se 5.6. Ive had a vibration problem in the front right tire for a while now. Ive tried 4 new tires. had them balanced and checked again. thinking it might be a bad tire I had them rotated. No help and also rules out a bent rim. then I thought maybe warped rotor so I replaced all 4 with drilled and slotted rotors and new brake pads. It didnt help the vibration but at least I got new rotors. its been about 4 months since replacing them and 2 days ago I noticed that a slight grinding noise coming from that tire. after looking at it the pad had worn down almost to the metal. the outer pad and all other pads on tires look almost brand new. what is causing the massive vibration and why did that one pad ware so much? it is the one against the caliper but when I changed the pads again today the caliper didnt stick or anything when I pressed them back. any thoughts would help thank you.