Since the problem is sporadic, it is probably in the oil pump or the screen or pipe on the oil pickup in the pan. If the screen or the pipe is loose, it can let in air which will cause loss of oil pressure. It could also be a stopped up screen in the oil pickup. GM lists the following as possible causes of engine oil pressure below spec: Oil pump worn or dirty Malfunctioning oil pump pressure relief valve Oil pump screen loose, plugged, or damaged Excessive bearing clearance Cracked, porous or restricted oil galleries Engine block oil gallery plugs missing or incorrectly installed Broken valve lifters Add to this, very low oil level. That's probably been checked, but in case it hasn't . . .
Cause low pressure oil pump
The most common cause of lifters knocking is low oil pressure.
Loose converter bolts or a cracked pressure plate.
A hole in the muffler would cause a knocking sound in your muffler. A loose exhaust pipe can also cause a knocking noise.
Check your flywheel. A loose flywheel can make a knocking sound and would do so almost instantly.
bad oil pump spun a bearing low on oil
Low oil or low oil pressure, bad oil pump, clogged or gummed up lifters or even thin oil can cause low oil pressure. All the possibilities mentioned can cause the engine to be starved of lubrication. Which in turn creates friction that heats the metal engine part so that their tolerances change. Change in tolerances between two parts can cause knocking with increased heat from this friction.
It may have lost oil pressure. Is the oil full? Insufficient oil is the most common but not the only cause of low oil pressure.
u knocking on it
Yes
No.
what engine?