Hey guys, I'm new to the forum, but will have a lot of questions as this thing progresses. Thanks in advance to anybody who has anything to contribute.

I've got this 2002 Taurus (12v) with about 155k mi, that has a handful of problems, but for now, I'll focus on just one. Today, I got to work, and sat in the car for just a minute before shutting it off. As I sat there, the RPM began to surge up and down between like 300-1000, and when it would get low, the oil light would come on for probably 1/2 second. Once the RPM went up, the oil light would turn off. Obviously, the light was showing because at low RPM the pressure is very low...but what's causing this? The surging of RPM, that is. PCV valve? Vaccum lines? IDK. Any insight whatsoever is much appreciated.

Also, when I'm driving at highway or even in town speeds, things are fine.

 

Check the Idle Speed Control motor to see if it is dirty. It could be a vacuum related problem also. Look at the the vacuum lines first.