A few months ago I noticed my oil pressure gauge starting to go all over the place on my 02 ranger 3.0L. When the engine is cold the gauge works as intended but once its warmed up as long as I keep the RPM above 1k its fine but if I stop at a red light/stop sign then the gauge drops and bounces all over the place it has actually bounced below the pin a few times. Any Ideas to what is causeing this?

Either your motor is about to blow up or you have a bad oil sending unit...

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2001 Ranger XLT SuperCab 4dr Flareside 3.0 V6

The engine itself seems to be running fine , no problems starting and it has never stalled on me. It's been like this for about 6 months or longer. Is the Oil Pressure sending unit hard to change?

no its not changed mine the other day hard to get to just go to ford and buy one then look for it because mine was under my intake but idk where on a 6cyl

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1999 2 wd4 cyl2.5l5 spd135k
MODS:5% tint all around Night Shades (Extra Dark)Corners Thrid BrakeTails Air silence removed 2006 Mirrors Flowmaster Super 44 (Weld on & Turn down)
35W 5000K Hids

on the 3.0L the sending unit is on the back of the block on the passenger side. Kind of hard to get a wrench on it without moving some stuff. I have not changed one on a newer one than 94. On it I just pulled the distributor for some room to get on it with a set of channel locks. That was with a five speed manual. I just looked at mine which is a 2001 with an automatic. Looks like a tight fit with the dipstick tube. Maybe if you take the valve cover off or pull the cam follower out you can get a wrench on it easier.
R

For the 3.0L, try looking in through the wheel well with the rubber splash shield pushed out of the way. It's buried back behind the passenger side cylinder head.

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2003 FX4 Level II, Supercharged 5.0L V8, Headers, Duals
BW4406 manual transfer case, Aussie Locker, Torsen L/S, 4.10's
Bilstein 7100 rezzies, Cadillac/Mustang rear discs, Duff traction bars
Keypad Entry, Lock LEDs, ABS switch, sway bar discos
Heated seats, Explorer EATC, Trip Computer and consoles

2003 XLT 2.3L M5OD-R1 reg cab, 2011 Taurus SEL, 2016 C-MAX Energi Plug-in Hybrid

Just an update, For the past 2 oil changes I have been using frame oil filters and roughly 2 weeks ago I changed my oil only they did not have any frame filters in stock so I picked up a Motorcraft oil filter and my oil gauge problem has been gone ever since changing my oil and filter. Dunno if this is just a coincidence or what or possibly the 2 frame filters I had prior were bad? All I know the problem seems fixed now and I have not change the oil pressure sending unit.

Do not ever, ever use a regular Fram oil filter...yes, they are that bad.

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2001 Ranger XLT SuperCab 4dr Flareside 3.0 V6

I always use motorcraft. Hard to beat what comes from the factory. Around here they even cost less than Fram.
R

Did you ever get the problem with your Oil Pressure Gauge resolved? Mine does the same thing. It actually was so bad it went beyond the stopping point. The "check guages" light comes on too.