question lang po nga diselpeeps,

napuna ko last Sunday parang paiba-iba yung feel ko sa engine ko... I mean... syempre family day so L3-VV and gamit ko, I started out ok, I mean the usual... steady and smooth. After church so andar na ulit kami, parang magaralgal yung tunog ng makina - tipong galing cold start - weird. Then pag-alis namin after lunch ok na naman, as in smooth ulit sya... i'm sure you know when your engine is smooth so to speak. Then on our way home parang gumaralgal ulit. Hindi naman garalgal as in parang nagkikiskisang bakal - as i've said parang galing cold start - aba eh hapon na yun... pinaka matagal na nahinto yung makina within the day was approx. 4 hrs... what could be the problem kaya? do you guys also experience this?