I have a 98 Dakota 3.9L and my oil pressure gauge goes way way down at an idle and back up to half when you give it gas. should it stay at half all the time or is this common for the beast??. I just bought it so im not sure

 

no that's bad. the pressure gauge should read normal as soon as the engine is started. assuming you have oil in the motor you may have a bad oil pump as the gauge seldom fails

 

Mine is always at about 3/4. Never moves. Even when I didn't have oil in it once (oops!)

 

i just had this same problem. i just bought the truck and before i got a chance to change the oil, when i first started it in the morning it jumped right up, but after a couple of start and stops it would sit on zero and then go up to 40 real slow. i changed the oil to castrol gtx high mileage and added a quart of lucas and now it is steady at about 43, never goes down.

 

I have a v8 1500 ram sport.

My oil light comes on and the gauge to zero. When i mash the gas over about 1500 rpm
the needle comes back up and the light goes off.

Is there a way to test the sensor to see if i get pressure (using a manual gauge)
and where is it???? !!!!!!!!!!!

If it is the oil pump, can it be cahnged without removing the motor? jusy the sump..??

THANKS GUYS>

 

Just checking but, you did check to make sure the oil is full right? also you should be able to access the pump by dropping the pan but it will get pretty messy. and, before you change the pump you should be able to hook up a gauge inline with the pump to check pressure. hope this helps. good luck.

 

Yes it is full of oil i just changed it.

 

Personally, my gauge is about 1/2 way at idle, and, at highway speeds (65-80) it's about 3/4 up there. Pretty good oil pressure on my 3.9L.

You can check the pressure with a mechanical gauge (or, you can spend the cash and get a replacement electronic one). However, I would probably agree with kurbycar32 (even though, truthfully, I haven't been around cars for all that long of a time), about the sending unit being pretty reliable.
I mean, it doesn't look horribly hard to R2 (remove and replace) the oil pump, and, even if it wasn't the pump (and it was the sending unit), well, at least you know you got a new oil pump!

 

my oil pressure gauge jumps up to about 3/4 way when i start the truck, but jumps down to about a quarter when at idle. then when reving or driving it goes up depending on speed, never past 3/4 and never below about a 1/4 though, my dad tells me this is normal but for some reason i dont think so. any ideas? is this bad for my truck?

 

The minimum oil pressure for both the 3.9L and 5.2L is 6 psi (at curb idle). The maximum oil pressure is 30-80 psi (at 3,000RPM or more).