1996 Isuzu Rodeo ticking

Ok I have a 1996 isuzu rodeo, I bought it with 125,000 miles, and when I first drove the car it sounded fine, now almost two months later it has develpoed a ticking or tapping like sound from under the hood, the engine runs smooth and strong minus the ticking noise, its not a perfect grade a engine anymore im sure but its strong still, anyway, I have read reviews and blogs about ticking in the 96 and alot of them say the timing belt, a mechanic said it was lifter noise, I havent explored these possibilities much, but what else could it possibly be, it dosent drive rough persay, and dosent shake and rattle or anything, but when I accelarate the ticking gets more frequent and louder and when I idle its stready, please help me anyway you can, the winter drive dosent work either, and im pretty sure the 4 weel drive dosent engage hope that might help