Engine sounds bad when cold
How long does the oil pressure light take to go off when you first start it from cold. Does it go off straight away as soon as the starter cranks over or does it go off when the engine first fires. It should be going off as soon as the engine fires, but not before. If its going off as soon as the engine starts cranking then its building pressure too quickly and would indicate an oil blockage. If it lingers on for a second or too after the engine is running then that indicates a possible low oil pressure problem.