.... but not lately

My oil pressure gauge is not working, however, when I replaced the sender unit the gauge worked well for about a week.
When it stopped working I again replaced the sender unit and it, AGAIN, worked well for about a week before returning to its natural state, i.e. not working. I have done this THREE times and am getting low on the readies for more sender units.

Any ideas anyone?

I have already checked the wiring from the rear of the cluster and from the engine compartment, however I have only checked the actual ohm's from the sender unit to earth the first two times. I have also replaced the actual oil pressure gauge itself once. Made absolutely NO difference.

are you screwing the sending unit into the block enough? maybe its working its way loose?

have you checked the connection from the wire to the sender, that may also be working loose?

The third time I solder tacked the wire to the sender units connection.
The unit itself was in tight when I replaced it those three times.