My 85k mile '00 XK8 has been warning me about low oil pressure for as long as a split second. I don't notice unless I'm looking at the gauges or the warning cluster. The gauge itself flickers between the middle and the low pressure mark for a half second. I noticed this usually happens when I am idling on a steep incline.

There are no other symptoms besides that. When I first saw this I freaked out and turned off the car on fear of toasting the engine. I checked my oil and noticed it was topped to just slightly below the full mark on the dip stick. After starting the car again I noticed the warning was gone and didn't return at all during that trip. This started happening yesterday when I first drove the car after about 4 or 5 days of commuting by bike to save on gas.

So far, I've only seen it come on twice and I have driven 47 miles since the first event.

 

Unless you have converted to the Real Gauge oil pressure system your gauge is only telling you that you have at least 7psi of pressure . . . or not. Problems could be a bad sensor, clogged oil pick up screen or worn engine. Have you had a tensioner come apart? The broken pieces of plastic can restrict the flow through the screen.

Since you have to remove the sensor to attach a real pressure gauge I would probably just replace the sensor. The sensor is a $16 part at AutoZone and would quickly resolve that question.

 

No, I do not have the real gauge nor have I had the tensioners come apart. I already upgraded to the third gen tensioners.

Where is the sensor located? What is the part number?

 

The sensor is located between the oil filter and the block.

Duralast/Oil Pressure Switch PS541 at AutoZone.com

 

Today I drove about 55 miles and I never once got the low oil pressure warning or saw the gauge flicker.

Did it correct itself?

 

You could be dealing with an intermittently-failing sensor. You may want to start by pulling it, cleaning it, cleaning the electrical connections, and re-installing it....

 

The chain guides and primary tensioners also shed plastic as they age, which can clog the sump before you have any symptoms. The sensor switch is the easiest and is cheap to replace though before you do anything else.

 

Alright, I guess I'll get to work on that first.