cam Belt broke on my daughters Palio 1.6, I replaced valves, all running perfect.2yrs down the line cam belt breaks again, replaced valves and tensioner, but now like a loud tappet noise coming from engine. Engine starts easy and revs perfect, lots of power, but after 2 Km it loses power, and battles to start, leave it to cool down, and same thing, starts easy, lots of power, goes 2Km`s and loses power, please help me, thanks.