Some times it has a loud knoking when you start it up! oil presure good.

TRY CHECKING OIL PRESURE WITH A MANUAL GAUGE IF IT CHECKS OUT GOOD THEN CHANGE OIL PRESURE SWITCH

90psi compression is low in some cases engine may run but will be very weak and stall after a short time. a good petrol car compression should be between 120 to 150psi.
Does the engine oil light turn off after started, make sure u have oil pump up to the head, check the oil pick up inside the sum. The engine valves should not and never bend from no reason.

Check the oil pressure with a mechanical gauge, I think you have a low oil pressure

Blown piston or rod. Scrap the car. Not worth fixing. $2000 repair.

Check oil. Presure sensor

maybe it's ur gauge! you can get it pressure tested at ur local auto shop for pretty cheap i think! Sounds to me like its nothing major as long as you know you got oil pressure! ( check temps while driving) BUT i wouldn't worry to much about it as oil pressure tends to flux as car is driving/ getting warm and oil gets lighter. Worst case scenario is a leak in the timing cover gasket and whoever replaced it should cover it. Do you see an residual oil near it? or on the ground when its wet and you pull out of your parking space? Hope this helps!

yes sounds like you have a rod knock how ever there is a possibility your engine will last you like that for a long time

sounds like you lost oil presure and have major engine problems

if you've got a few $$ to risk ,try some synthetic oil with new filter ...it often work good for these kind of noise as long as it is not a loud knoking nois ...if it is only a fast clic clic nois it will probably work!

You are going to need to remove the oil pan and clear the pump pickup screen. After replacing the pan, put one gallon of marvel oil and one quart of kerosene in place of the engine oil. remove the distributor and make an extension for an electric drill so that you can drive the oil pump with the drill (there should be a hex drive rod that fits into the end of the distributor) Run the drill to circulate the solvent, then let it sit for a few hours. Run the drill again then drain the pan. replace the filter and fill the pan with the correct amount of cheap oil. After replacing distributor, start engine, check oil pressure..If good, continue running for about a half hour. Change oil using good quality oil and add more marvel oil (no more than 1quart) Afterward, you can drive about 1,000 miles, then change oil and filter again and resume regular change intervals. I know this is an elaborate procedure but I have done it many times with good results. Providing the lack of oil when you first started the engine has not damaged anything, you should be OK.