2002 Ford Focus SE… Oil Pressure Light Flickering?

I bought an '02 Focus SE back in November. So far, I’ve replaced the first fuel injector (cyl 1 misfire), kept up with oil changes, and all my fluids are good.

The issue is my oil pressure light flickers—not flashes, but flickers like a dying lightbulb. It only happens after driving about 24 miles on the interstate, usually when I’m slowing down in my driveway.

My dad thinks it could be a bad sensor or something more serious, but we’re not sure. I have an appointment at the shop, but it’s a week out. Any tips in the meantime?

First thing to check is the oil pressure sensor—those are common to fail and cause flickering lights.

If that’s not it, it could be something more serious like a failing oil pump or an electrical issue. Have you checked for any error codes?

@Emory
Thinking back on what I’ve done so far—could this be happening because I haven’t fully finished my tune-up? I replaced the first spark plug twice, then the fuel injector for that cylinder. I have all the parts, but the shop gave me the wrong wires (Zetec instead of SE), so they’re a little longer. I also have a washable air filter that I haven’t checked in a while.

I don’t have the right wrench to get in there myself, so I’m just waiting to drop it off Monday.

@Pax
If the oil level is fine and looks good, it’s more likely to be an issue with the sensor or wiring rather than the tune-up.

A real oil pressure issue would usually cause rough running or knocking, not just a flickering light.

What exactly do you need tips on? If you already have a shop appointment, they’ll diagnose it for you.

Lane said:
What exactly do you need tips on? If you already have a shop appointment, they’ll diagnose it for you.

My appointment is a week away, and I just want to make sure I don’t make things worse while waiting. I lost my last car (a Fusion) because I ignored a warning sign for too long. Just trying to avoid that again!

@Pax
If an oil pressure light comes on, the first thing you need to know is whether it’s an actual oil pressure problem or just a bad sensor. The safest way to check is to remove the switch and install a mechanical oil pressure gauge to see what the pressure actually is compared to the manufacturer’s specs.

@Lane
Oil level and color look fine. I don’t have a tachometer, but the car sounds normal to me for its age. What’s the oil pressure switch?

Pax said:
@Lane
Oil level and color look fine. I don’t have a tachometer, but the car sounds normal to me for its age. What’s the oil pressure switch?

It’s the sensor that sends oil pressure readings to your dashboard. If it fails, it can trigger the light even when oil pressure is fine. The only way to be sure is to test actual oil pressure with a gauge.

Does the light flicker every time you slow down or just when you’re parking?

Jin said:
Does the light flicker every time you slow down or just when you’re parking?

It flickers when I slow down while still in gear. If I’m in neutral, it doesn’t happen unless I press the brakes hard.