Help with a Grounding Problem

[R. R. ( Rick ) Jones]

I washed the top & bottom side of my engine with Gunk spray and then a hose trying to clean enough to see some small oil drip locations. I've done it before with no problems, but this time both my gas gauge and water temp gauge have gone crazy and pegged out off the high side of the range. With the key off they're normal, but when the key is on they go off the high side and stay there ??

I figure I've done something to the ground somewhere, somehow, but what & where ??

Any ideas ??

Thanks