hello. i got a huge problem. got lexus sc400 95' and had the orange symbol with the oil level. i ignore it and didnt fill oil for a week or so. few days ago while driving my RPM went into 0, and after 5-10 sec red symbol with low oil pressure arrived. i stopped the car and run it again. it all worked. the same day i replaced the oil with filter. and now it happens often. sometimes after 5 minutes of driving , sometimes 30 minutes. and i got no clue what to do. in my country there arent so many good mechanics, and i am afraid that if i leave my car to the bad one, i will cost me alot, and problem will not get solved. what could it be /// i think the engine couldnt get damaged, because if it is the car would have the problem for all the time. and now sometimes its driving without problems, sometimes its stopping.

did you manually checked with your dipstick how the oil level is ? that will be the most accurate way to check your oil level
did you check for oil leaks ? burning oil or a leaky head gasket (white oil contamination ) ?
after a oil change most of the time you need to fill about a half a liter (1/2 quart) up to a liter
start with 4 a 5 liter of oil then fill her up to the right level

w/oil filter change = 5.3 liters (5.6 US qts, 4.7 Imp. qts)
w/o oil filter change = 5.0 liters (5.3 US qts, 4.4 Imp. qts)
Dry fill = 6.0 liters (6.3 US qts, 5.3 Imp. qts)

Well considering his oil pressure light came on and the car stalled out it's a safe bet to assume his oil level must have gotten extremely low for the oil pressure light to come on.

It's very possible that the engine may have been damaged from oil starvation at the time. Driving now does the car still stall out from time to time, or is it just the light thats coming on while the car no longer turns off?

the car engine stops while driving, and the red oil pressure light arrive. then i stop the car, and run engine again and carry on driving. on monday i put the car to the mechanics so then i will know what is going on. hopefully.