For starters, it's an oil pressure gauge, not temp.

Secondly, all those gauges share a common ground point, so it's about a one in one bazillion chance that all the senders failed all at once.

Take the kick panel off by the clutch pedal (below the fuse box) and check the ground point there. It should be securely attached.

If that doesn't solve it, you'll probably want to pull the cluster and check the wiring going into it.

My Truck: 1987 XtraCab DLX 22R 4WD 5 Speed Manual
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"Speed has never killed anyone. Suddenly becoming stationary, that's what gets you." -Jeremy Clarkson