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Howser 03-26-2010 09:24 AM

'02 Ranger jittery oil gauge
~100K miles. 3.0L Manual transmission. Problem started last summer. Would only do it on longer drives. Turn off truck, start back up, would be OK until driven a while. Always changed oil and filters at regular intervals. No leaks. No smoke. No rattling, grinding, pinging or other noises. No antifreeze in oil, or oil in antifreeze. Spark plugs look OK, all exhibit similar wear, and were changed at 83,000 miles.

Always only does it after fully warmed up, and only as coming to stop, and settled to idle, but intermittent.

First, replaced sender. No help. Shortly after, noticed CPS was starting to squeal. Had that replaced. Still did it.

Replaced sender again with higher quality one. No difference.

Had a mechanic temporarily connect an actual oil pressure gauge and monitor it. Said it was actually still pumping oil, and SHOULD be safe to drive. He also temporarily installed another sender, but that didnít help.

What I have noticed, and he agreed after I mentioned it, is that after good and warmed up, and coming to idle at a stop, sometimes the tach shows the idle to drop a few hundred RPMs, and the engine seems to idle a bit rough. Thatís when the gauge bounces. The slightest bit of throttle causes the gauge to stabilize. I have no idea how accurate the ďtachĒ is (if itís anything like the speedometerÖnot very) but on a cold start, it goes to just over 1000, maybe 1100 RPM. After short runs, it idles to just under 1000, maybe about 800 RPM. When the gauge starts bouncing after longer runs, it seems to drop to what would appear to be about 600 RPM, and idle a bit rough.

So, Iím starting to wonder if the lowered idle is causing the oil idiot-gauge to not see quite enough pressure to work properly, and causing the bounce? Iím wondering if something in the emissions control system is causing that?

I cleaned the IAC valve and throttle body. I also cleaned the MAF sensor. Helped smooth things a bit, but still has the problem. I suppose it still could be a bad one of those? Maybe the IAC valve isnít working quite right, and causing low idle after warmed up?

How about the ECT sensor? Could that be fooling the engine into thinking itís too hot, and thus, trying to reduce idle to cool down? Is that how it might work?

Iím fairly convinced the jumpy gauge is caused by the lowered idle. Does that make sense? Or, am I chasing the wrong thing?

Iíd appreciate any ideas. This is driving me crazy, and Iím nervous about driving much at all until itís resolved properly.



JDMerk 03-27-2010 05:53 PM

Re: '02 Ranger jittery oil gauge
I've noticed the same thing with my 03 auto 3.0
It only seems to do it when its very hot out and I have been on the highway for an extended amount of time. It seems to be worse when I have been towing i.e. O/D off (higher sustained rpms)
I pretty much came to the conclusion that due to the sustained high rpms and the light oil weight (5w20) that the engine was frothing up the oil and at idle it was pulling in the bubbles and that was the reason for the "jitters". My solution was to switch to a heavier oil during the summer months (10w30) and back to the regular oil when it gets cold again. Seems to have effectively solved my jitters.

rangerak 03-27-2010 07:22 PM

Re: '02 Ranger jittery oil gauge
I had the same symptoms shortly after I got my 2001 3.0L except for the idle was ok. The truck had 86k on it and appeared to be poorly poor maintained, just driven. It was ok until I did some rapid oil changes of motorcraft 5-20 synthetic blend every few hundred miles until it cleaned up. After the fluctuation happened (only the one time) I changed to Castrol Edge 10-30. The engine used a little oil at first 1/2qt in 1k at first but once I changed to Edge it went 10k without any usage at all. I changed the filter at 5k and at 10k changed oil and filter. I left the 10-30w in over winter without any problems. Just let it warm up good before going anywhere=no problems for me.

dprozzo 04-15-2010 09:26 PM

Re: '02 Ranger jittery oil gauge
I'm having exactly the same problem with my oil pressure gauge. Next oil change I will try 10W30.

edgeman4.0 04-15-2010 09:32 PM

Re: '02 Ranger jittery oil gauge
if i'm not mistaken, there was an issue with the oil pressure sending units on the 3.0's. seeing that op has already replaced his twice, could be something with the wiring or the gauge itself.

dprozzo 04-19-2010 06:38 AM

Re: '02 Ranger jittery oil gauge
I replaced the oil gauge (the whole instrument cluster, actually), and this did not help.

snguyen1983 06-29-2010 08:31 AM

Re: '02 Ranger jittery oil gauge
Hello Howser. Did you ever fix the problem with the oil gauge?

snguyen1983 07-03-2010 05:52 PM

Re: '02 Ranger jittery oil gauge
My gauge was doing the exact same thing as Howser mentioned. I noticed that the previous owner did his last oil change with 5W20. I decided to replace the oil with Castro High Mileage 10W30 with a Motorcraft oil filter. The "jittery" gauge issue went away for a few days, but now it is starting again. It happens sporadically and it is not as flickery as before.

The oil pressure switch has been replaced.

Does anyone have any other suggestions?


dprozzo 07-04-2010 11:04 PM

Re: '02 Ranger jittery oil gauge
Well, replacing the oil pressure sending unit *appears* to have solved the problem. FWIW, it I bought the replacement at O'Reilly Auto Parts for about $8.

Replacement wasn't easy as the unit is in a place that is difficult to reach, near the base of the tube for the transmission fluid dipstick, accessed from the passenger's side. The connector at the end of the green/white wire pair has to be unplugged. I used a 21mm deep spark plug socket with a 1/2" drive and one of those universal "knuckle"-type thingies to remove the old unit. Even so, it was very hard to line the new unit up and get it started without cross-threading. There was very little room to get my hand in position. Good luck, it can be done.

BTW, I have no idea why replacing the sending unit appears to have worked for me but clearly didn't for the OP. My gauge got flakey under exactly the same circumstance that he described, tho I can't say I felt the engine running rough at the time. Tapping on the gas did stop the jitteriness, just as he said.

I've had the new unit in place for about 2 months now and I've not had the problem come back. If I notice it occur again I shall let you know.

jswatson 07-27-2010 11:30 AM

Re: '02 Ranger jittery oil gauge
I've got a "flakey" jittery oil pressure gauge also (Ford Ranger XLT 2002, 3L, 6cyl).
Exact same symptoms ... only flakey at idle, after driving for a while on freeway.
Turn engine off, and then back on it goes away until next idle.
If you aren't looking at the gauge, you'd never know there was a "problem".

It's been doing this for about 4 or 5 years now, so I'm kind of think its not
a big problem, but seeing that gauge get jittery still makes me kind of nervous,
and I wish it could be fix, but I don't feel like spending a bunch of money on it.

Danger Ranger 03 07-04-2011 03:30 PM

Re: '02 Ranger jittery oil gauge
I've had the same problem with a twitching oil gauge for over a year. I also have reason to believe the camshaft Synchronizer my need to be replaced because I sometimes have a chirping sound from the engine rear. I have driven it from Michigan to Colorado this summer & last summer and it's still holding up. Does anyone know if the synchronizer could be causing both problems?

jswatson 07-05-2011 10:30 AM

Re: '02 Ranger jittery oil gauge
My "flakey" oil gauge finally just died (flat lined ... just read zero ...) about six months ago.

It didn't seems to bother anything, so I didn't get around to getting
it fixed until recently (another 20k miles).

They charged $270 to fix it ...

Now it works again, but it is again still "jittery" once it warms up.

Christianguy 07-05-2011 10:45 AM

Re: '02 Ranger jittery oil gauge
Yea... My 1999 3.0 gauge also has the jitters!
I do notice that it happens on long hot drives,
But it goes away with in a few minutes.
My maintenance is spot on, so unless it STAYS on
Low pressure ,I don't worry about it!
It sucks to see idiot lights and gauges go haywire!

Howser 07-07-2011 03:44 AM

Re: '02 Ranger jittery oil gauge-update
Figured I my as well update this.

After talking with several mechanics, So, after trying a bit of a heavier oil, and that didn't do the trick, I decided to try a bit of Lucas Oil. Several mechanics recommended it (including my uncle), and said it 's good stuff and wouldn't hurt anything.

The truck has a bit over 100K miles, and I figure that maybe it's worn just enough somewhere in there that it isn't feeding the sender QUITE enough pressure when it's hot, and it comes down quickly to idle.

Since it's been running the recommended 5W-20 since new, I figured the combo of slight wear and thin oil may be contributing. So, after experimenting through a couple of oil changes, it seems to be fine adding about 4 qts. of oil first, adding about 1/2 bottle of Lucas, then topping it off with oil.

I've only seen the gauge jump, mildly, a couple times since I started doing that...and that was after long drives on the highway. It seemed the engine also had just a slight little 'hiccup' after decelerating to idle, and that's when it happened. Otherwise, it seems fine.

I have religiously maintained the truck since new, but, it's a machine and all mechanical parts wear, eventually. Anyway, seems fine, for now.
It definitely doesn't smoke (the tailpipe looks clean as new), and runs fine otherwise. Seems thickening up the oil...just a bit...helped.


RevPaul 07-09-2011 07:11 PM

Re: '02 Ranger jittery oil gauge
My truck has done the same for quite some time. Recently, due to the jitters, the needle on the gauge flipped completely around counter-clockwise and was stuck below the small pin it normally rested on. I had to open the dash and use a small wire to catch it and move it back into position. I did not want this to happen again, so I had the oil pressure sensor replaced. Now, it will still have the jitters, but not so violently. I use 5w-30 Valvoline Max Life, and have used that for some time. I change engine oil every 2-3 thousand miles. It does not burn oil or leak, and I am exceeding 224 thousand miles, (on my way to 400!).

By the way, the mechanic searched for the sensor location for nearly 2 hours, getting bad advice from friends. Fortunately, I was only billed for 1/2 labor after I brought in my Haynes manual and found it in an illustration.

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