I have a 95' Beretta. It has no gauge for the oil pressure , just the warning light which comes on every so often. When I got the car the old oil was pretty bad (thick and black). So I flushed it with GUNK oil flush and drained and replaced. I put 10w30 Quaker state, instead of the recommended 5W30. Could the pressure get low because of the slightly higher weight oil? Could the screen in the pan be clogged? Senor? Any help would be great! Thanks.

No, if anything it would be higher. Most likely someone was running 10-40 or even 20-50 weight to keep the pressure high enough to keep the light off. Heavier oil will raise pressure, but, according to many, can do a lesser job on engines, especially in winter. If the engine has a lot of wear, you might want to run a 10-40 to help out, or a 0-40 synthetic. First though if you have any way of getting a true oil pressure test done cheaply, you might find you only need a new oil pressure sender unit. Could also have a plugged screeen on your oil pump, but you would have to drop the pan to be sure.

DO NOT put synthetic in it by any means. It will wear your seals down. Flush it with 5W30 and try changing the oil again.. it also could be a defective filter. Could be your oil pressure switch too.

why are so many old topics being brought up lately?... this guy prolly dont even own this car anymore... but if you are the one who originally posted this, shotgun it replace the oil pump, oil pressure sending unit, and replace the oil and filter all at the same time...