The oil gauge in my 2004 toyota sequoia reads sporadically, anywhere from no oil pressure to high oil pressure. I'm guessing it's the oil pressure sending unit. Where is it located on a 2004 sequoia?

put mechanical pressure gauge to see if pump or gauge is problem

replace the oil pressure sender unit ( not the pressure sensor unit) as it appears to be faulty and stuck giving the wrong reading.

caliper to spindle front?
i guess you never heard of the FSM book,sold for every car made.
and the virtual books.?
alldata.com (google it)
or the offical page.
helm does TOY. for MO- BUCKS

http://www.helminc.com/helm/search_service_owner.asp?Style=helm&class_2=TOY

some one here will look it up for you, i have no toy accounts.

Location: drop your skidplate then it is located right by the oil filter

when you fit a compressor . after vacuuming the system for about an hour, you connect the gas up to the suction port and let the gas in
with the engine running and the ac switched on , when there is enough in the system the low pressure switch is turned on and the compressor starts to run sucking in more gas
The system is charged according to pressure gauges and not by the number of cans
now you are doing several things wrong
1-- there are 2 types of gas and if you used a wrong replacement unit , it will not handle the high pressures of the different gas
2-- if you used the no of cans method -- then liquid freon gets to the pistons in the compressor and hydraulic locks the system resulting in the destruction you describe
3--- did you put oil in the compressor before fitting it
as the oil circulates with the gas and there was no oil i the replacement compressor , then the plate runs dry and seizes , again causing destruction
the best method is to get an accredited ac professional to do the job or it will cost you more money

Have you thought maybe the gauge is bad?

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/sean_54c3a3dc48a7773c

have an oil pressure test performed - should only cost around a half hour of diagnostic labor. this will tell you if you have a real oil pressure problem, or a bad sensor.

There is no Special Service Campaign on that issue. There is, however, a TSB on that issue, and the fix is to replace the sending unit and the gauge.

The oil pressure sending unit is a sensor with an internal diaphragm, if the internal diaphragm is damaged , or the line to the diaphragm is blocked you can get this kind of fluctuation on the oil pressure gauge.

The oil pressure value must be read by installing a mechanical gauge near to the oil pressure switch and checking the pressure.

If pressure is ok, replace the sending unit. If there is a real pressure drop, check the oil pump.

If you still get fluctualtion after replacing the oil pressure sending unit, replace the oil pressure gauge.