I bought a BWP or BWB (cant remember what brand it was exactly)sending unit
from advanced auto. It worked, for half a day. I returned it and got an actual MOPAR version from a dealership. It worked, for half a day to. It was all good for about probably and hour and a half of driving and now it says the oil pressure is 0 when at idle or we slow down any and back to 40+ when we take off again. What now?? im at a loss

Test with mechanical gauge. And stop driving it til you do.

Mine works fine.

Maybe your motor is tired?

Could be sludge in there. I run 1qt of transfluid in the oil 500 miles prior to change to clean it out. Walmart version is $2 a qt. Although, any will do. Been doing this for over 10yrs. on all my vehicles. The oil on dip stick is so clear, you can barely see it after.

and what would i do if the gauge is allright?

Clean the hole where the sender screws into the block before you hook up the gauge. If the gauge reads like it should, retry your sender. And clean the connector and check the wiring as well. I guess potentially you could have had crap luck with bad senders of all that checks out.

Like mentioned above, some of these are bad about a pocket of sludge clogging the hole that the sender goes into. You can dig a pic or small scredriver in there, maybe a pipe cleaner too. What some people do is when the sender is out then start up the jeep for 3-5 seconds to use the engines oil pressure to blow the hole out. Just be prepared for a small mess.

It will still be a good idea to have a mechanical guage to verify actual oil pressure too.