Engine knocking When perfoming cold start, the engine knocks loudly for a while and then quiets down. After driving for a while it starts again but not as loud. the car then starts to lose power

Oil pressure issue

it sounds like a critical internal failure is eminent . if the oil pressure is ok,it could be a bent or broken valve as the exhaust leak can let the valves cool to fast and warp. however it sounds more critical than that. do a compression test on that side and see if the #'s are consistent.

Not sure on model but to me sounds like its a dodgey valve lifter when the seals start to go they cannot hold the oil and when there under pressure they basically empty them selves hence when you turn the engine off and restart you get a rattle sound untill the valve fills again as long as the cars running ok leave it untill you have to replace them unless there easy to do sone are sone are a pain

it could be a big end bearing i dont know where the knocking sound is comeing from but if it is your piston and conrod may be comeing loose then by that time u may need a new moter but can be repaird at a less cost u should not be driveing at all

sounds like a sticky lifter that sometimes is mistaken for a knock chevys are notorious for them and can run forever on it. check the oil for grits or metal flakes

That is an indication of worn internal engine parts, it quiets down when warm because the metals expand tightening up the fit between parts. If it is a true knock then the parts that are most likely worn and causing it are main/rod bearings, or piston bores/rings.

Sounds like a hydralic lifter issue. These lifters operate the cylinder valves and run off oil pressure. When the engine is cold and the oil is thick worn lifters tend to rattle. When the engine warms up, everything expands and the lifters stop rattling. There is no easy cure for this except replacing the lifters. Sorry....

It could be the compressor is going out, or the clutch itself is worn out. If the AC still gets cold, then it is the clutch.

well if u will use a higher octane rate then this voice will be cancelled or try to check ur knock sensor if it works ( if ur vehicle has this sensor)

you are abouot to lose the motor,,,,you have a rod knocking when you start it up and an oil pump wont help it been there done that all it does it make it worse