Oil Pressure Gauge

[Glow Worm]

While stopped at a traffic light I noticed my oil  pressure gauge (1973 Cuda 340/factory gauge) needle dropping.  When I accelerated, the needle slowly climbed back to normal, and stayed there until I was putting the car in the garage, and then the needle started to drop again.  It was late, so I didn't mess with it that night.
The next morning I went out and checked the oil level, and checked to be sure I had a good connection on the oil sending unit.  The oil level was exactly on "full" so I started the car, and the gauge needle pegged to the top (max) of the gauge.
I shut the car off, and the needle stayed pegged.  After sitting for 12 hours, the needle is back to the bottom of the gauge.
Any suggestions? 
NOTE: The car had some major work done recently, and I am not sure if this is the "old" sending unit, or if it was replaced during the upgrade.  A new under dash harness was installed, as well as a new engine bay harness.  As far as I know, all of the gauges are factory original.

[Cuda Cody]

It's normal for oil pressure to drop a little bit at idle when compared to driving at a higher RPM.  And when oil is cold it will also build more pressure so it will show higher right when you start it up.   If you want to check your gauge this might be of some assistance:

[Cuda Cody]

Also, Welcome @Glow Worm    to the site.   

One more thing.  I think the Rallye gauges do use a different sending unit so it might be worth checking to see if you have the correct one.  Maybe it got replaced with the rebuild with the wrong one?

[Burdar]

If the gauge voltage regulator isn't regulating the voltage, it will peg the gauge.  It will burn up your gauges in a hurry.  Was it just the oil pressure gauge that acted up or all of them?

[Cuda Cody]

   I've had that happen to me too.  It will peg the needle if you turn the car on without even having it running.

[Glow Worm]

Thanks for the Welcome....!!!  I am happy to be a part of the organization.
I've been posting on facebook for awhile and thought I was already signed in to the site.

The only gauge that acted crazy was the oil pressure gauge.

Can anyone, please, provide the OEM (or replacement) part number for the rallye gauge oil pressure sending unit?
Thank you!

[Cuda Cody]

@MoparDave  has OEM factory replacements and if you tell him you are with the E-Bodies group he will take super good care of you.

Thanks for the Welcome....!!!  I am happy to be a part of the organization.
I've been posting on facebook for awhile and thought I was already signed in to the site.

The only gauge that acted crazy was the oil pressure gauge.

Can anyone, please, provide the OEM (or replacement) part number for the rallye gauge oil pressure sending unit?
Thank you!

[erik70rt]

The only difference in the originals is one is for a gauge and the other is for a light.  You need the one for the gauge.  They are pretty common. 

https://www.napaonline.com/en/p/ECHOP6603

[MoparDave]

3488609 was the current servicing part number and is now NS1 discontinues, the standard number is PS59 which we have in stock if you cannot source that locally.

http://www.rosevillemoparts.com/advanced_search_result.php?keywords=ps59&search_in_description=1&imageField.x=0&imageField.y=0

[Glow Worm]

Is there anyone "out there" who refurbishes e-body oil pressure gauges?

Can the gauge be removed without removing the entire dash?

[MoparDave]

Is there anyone "out there" who refurbishes e-body oil pressure gauges?

Can the gauge be removed without removing the entire dash?

rebuilding the gauge can be done and we have. the complete dash No. but The cluster will need to be removed to remove any gauge. so the light bar, switch pod, cluster dash face and housing. then the cluster housing can be removed.