Oil pressure sensor hints?

[imflyn]

Within the last week or two I've noticed my oil pressure decreasing as well. The temperature has warmed up from around freezing to 70's so I think that's part of why I'm just now noticing it. Cold idle I get about 40, but after it warms up the warm o/p is 22-25 psi. I have an A4 so in gear it idles around 600 rpm. When it's cold the oil pressure goes up to about 60 psi at 4k and warm the o/p at 4k is about 40 - 45 psi . I know this is lower than I saw last summer so I'm going to start with the sensor. I know it's behind the intake. Any helpful hints on how to change it? I was also planning on using autorx as soon as it arrives.

BTW I changed the oil less than a 1k miles ago w/ mobil 10/30 and mobil filter, and yes it's still full. I also notice something odd. When I'm on the highway and the t/c is locked up, if I give it a little gas the pressure goes down a couple psi and when I let off the throttle it comes back up a couple psi. Kind of weird. Maybe this provides some additions clues?

[9t8z28]

It sounds like the engine is beat up. Your crank seems to be quite worn. As you apply a load the crank seems to have excessive play. Your oil pres. is low. Mine is around 45 or more when warm.. I may be wrong as I may have overlooked something!?
I can't see a sensor causing this issue. Is it leaking?
How many miles has that engine got?

[imflyn]

I had the oil pressure checked with a mechanical gauge today and it was about 5 psi lower than the stock gauge said, 18 psi at hot idle...sigh. The mechanic said that 6 was the idle minimum and I laughed. So I got on the phone with a speed shop here in louisville and I'm going to visit them tomorrow and we can plan on what to do in the rebuild. He concurred that the bearings are probably worn, etc. and he didn't think a new oil pump would solve much, which I am inclined to believe. I just hate to condemn the engine before it's due, but I don't want to grenade it and really be up a creek.
BTW it has 118800 miles on the clock.