Subject: low oil pressure light comes on at low rpm?
Question:

1999 Eclipse GS-T
I'm running synthetic 15-50 oil and I have run sythetic since the
car was new. Every now and then the oil warning light would
flicker on and off at low RPMs (idle). I just changed the oil and
now it seems to come on and stay on at idle as long as the car is
warmed up. If I push the idle to about 1200 RPM it'll go out.

Do I need a heavier weight oil? If so what do you recommend?

Also, I read that there was a recall on the battery harness for a
malfunction that could lead to malfunctions in turn signals and
oil pressure light. Any possibility or just coincidental?

Thank you for your time.
Answer: Dan,
If anything, you should be using a lighter weight oil. You should be using a weight more like 10W-30. If you've been using 15W-50 for the past 6+ years, that will put extra strain on your oil pump gears, and will prematurely wear them down. Using a sythetic is a very good choice, though. That will help prevent wear, but it's still extra strain due to the very heavy oil, and your oil pressure sending unit and oil filter bracket relief plunger may also be wearing down. This can be especially straining on cold starts, and if the outside temperatures get very cold in your area. And if you're in a part of the country where it snows, you should be using 10W-30 in the winter, or even a 5W-30. The 15w-50 is good for areas of extremely high heat all year round (southwest US), or if you are racing with your car.

The only recall I've heard for your car (at least the ones built/sold in the US) is for the lower balljoint. The battery harness issue may just be in a technical service bulletin that was written up, but if is indeed a recall, you should have it fixed immediately.
Good luck!