My 93 RX7 is having some problem with the gas gauge. It works when it wants to. Example, 2 days ago I filled the tank to full and the gauge read that it was empty. Today it moved back up to full. This is not the only time that it did it. Or if I put half a tank in it takes a couple days before it moves to the correct position. Does any one have any ideas what I should do?

 

i dont think the needle will move when the car is off. but the needle also goes slow.. when i fill up my car.. i turn the key to acc to get the needle moving... maybe 5 mins after driving its at full.. thats just me

 

Do you ever hear thunking sounds when you stop or take off?

If so the fuel tank's internal baffles could be broken loose and blocking the level float.

Another possible reason is dirty contacts the fuel level mechanism. Either way you'll have to pull the fuel pump to have a look-see.

Dave