Crazy indications. . .

Today, as I was driving home with about a half tank of gas on our '86 Jamboree, I got cold. No problem, turn the heat on. Well, when I did that, my gas gauge drifted up to about 3/4 of a tank and the oil pressure needle went up to the extremely high side of normal. It normally rides right in the center between high and low. Electrical problem??? Any suggestions???
Crazy indications. . .

My guess would be inadequate ground to the dash. The guages are often grounded on a large printed circuit. Check to see that wherever that ciruit or cluster is connected to the chassis that it is clean. Also look for any missing screws that may be connected to the ground circuit and attach to metal.