When you figure it out, let us all know, 'cause I'm having the same issue.

Yes, mine just started last week. I ordered a new sensor with the help of reading all the posts here. I think it will solve it from the sounds of it. I am unsure exactly where it is located though. So a picture of a breakdown would be great!! I am new to the boards but have been reading them for about 6 months or so, well once my rear regulators went to crap. I have been a bonneville owner for 5 years now. It is the best car I have ever owned.!

I have the same problem in my 00 SE. My dad freaked out and said get it to a shop ASAP. The manual states "Any reading above the read indicated area is normal operating procedure." I did notice that my PSI went up when it was starting to get cold, around 20F. The manual also states that it "recommends" that you use 5W-30 oil 60F and below for prime performance. I also notice that if you are in the frigid states that you might want to use 0W-30. I have never seen or heard of a car using this weight.

I think on my next oil change I'll put 5W-30 Pennzoil in. Which means, I guess, they want 10W-30 for the summer months and 5W-30 for the winter months.

I will take it to the shop, but if all of you are seeing the same results does this mean that it is normal?

One thing you might want to check is the plug. I believe that if the sensor is unplugged the gauge will peg. The terminals could be a little dirty giving a poor connection. Clean up the connections and plug it back in and see if that corrects the problem.

One thing that was not mentioned during the entire discussion was "Is it recommended to drive?" My drive to work is around 6 miles. I also noticed that a constant "gauge noise" coming from the dash. You know the noise the gauges make when changing values.

Also I did find this, Danthurs, in another post about connections being dirty. I copied and pasted the reply the same issue from another forum.

Reply or answer from another forum, Link: 2000 Bonneville oil pressure too high - Car Dealer Forums

"My first guess would be the sending unit but I would test it. It should
work with a resistance to grnd. If it is shorting directly to grnd your
gauge would read high. Check the dc voltage between pos 12 vdc from the
battery & the ground leg going to the gauge. (Check on sending unit) If this
reads approx 12 vdc the gauge should be reading correctly. Check with the
engine off and wires disconnected also, if it reads 12 vdc the sending unit
is bad. There are 2 legs on the sending unit as I recall. One should close
an interlock relay allowing the fuel pump to come on after they system build
6 psi or so. This leg should show 12 vdc after required pressure builds.
Make sure these 2 wires aren't shorted together. Also could have a blocked
filter not allowing a good flow and causing a 100% grnd on the sending unit.
If this is the case you should hear the lifters chattering. See if it takes
a sec for the pressure gauge to drop after stopping the engine. Try changing
the oil filter, & oil if dirty. This is my interpretation without having any
prints on electrical system. Hopefully this will help."

I know for a fact that this would probable cause a false reading if the contacts are dirty. Also I will have my macanic do a Dyo on my PSI directly. Hope this helps everyone and thank you Danthurs for your help!

I have talk with my small town mechanic an he also thinks its a dirty censor. I asked him would grounding contribute to a false reading and he confirmed it as well as nullifying any replaced of parts. he told me it would cost ant where from 20 - 300 to chase the problem down.

Danthurs, It was not he plug...but one of the three censers. He unplugged one by one, then as I was in the car on the life I heard chimes. Ding Ding...the censer he chose made my PSI gauge to 0. I freaked, but he told me before as he took the cap off that oil would be spaying everywhere, which it was not. I love censers...and the ones that cost 70 bucks during the holidays...of course it could have been worse.

Glad you found it. And there was no damage to the engine.