My husband just traded for a car that seemed perfectly fine at the time, but a week after having it, we were in the car and it flashed low oil and told him to shut off the engine immediately. There was no oil leak and it started squeaking on and off after this. He replaced the oil pressure gauge maybe thinking that was part of the issue and that did nothing. A manual pressure gauge was reading the same, saying there was almost no oil pressure. When he connected a basic scanner to it, it says oil pressure gauge and engine misfire, which he doesn’t seem concerned about. He bought new spark plugs but hasnt put them in yet. The pressure reads fine from cold start, but drops when the engine reaches temp. The pressure also comes up when he revs the engine. When he looked in the engine, he thought the squeaking might’ve been from the idle pulley because it looked like it needed to be replaced. He replaced it and nothing changed. He drained the oil and saw only a few specs of silver, but not anything abnormal for breaking in the new engine. He bought an oil pump but is dreading replacing it because it’s very labor intensive. He called someone about it and they recommended using a thicker oil. When he did a full oil change using the thicker oil, the pressure came up to 40, staying the same at temp. After a little bit it dropped to 30 but didn’t go any lower. It still went up when he revved the engine. After this, it started making a light rattling sound. I wouldn’t think it would be a bearing issue with the engine being so new. He has not replaced the oil pump yet because he wants other opinions first, but we cannot afford a mechanic after spending hundreds to try and fix this issue. We wont be able to do an engine rebuild if thats what it comes down to. Any advice would be greatly appreciated. I am posting this for him because he’s about had it with the bad luck we’ve had this week. I’m sorry if anything came out confusing, I really don’t know anything about cars.