I have an '83 rx and my gas gauge only reads untill the tank is about half full/empty and then the needle just drops to empty. Is this a difficult fix?

 

New sending unit is $111 bucks, iirc, from Mazdatrix. Hardest part is getting the rusted screws out to replace the unit.

 

Does it read full when you fill it up??

 

it does read full when I fill it up

 

If you get a partial reading on the fuel gauge, but not a full sweep, the resistance wires inside the sender are most likely broke at the point the gauge fails to read.

 

My fuel gauge (83) does the exact same thing. Reads full after filling, and for the first ~100 miles it will read somewhat accurate. After that, it's hit and miss. I have learned that a hard right hand corner will bring it back to a reading, for a couple minutes......
I just fill it up, and reset the trip odometer, then I start looking for a fuel station after around 250-300 miles, depending on whether I have been in town, or on the highway.
One of these days, I'll get around to pulling out sender, and see what's up with it, perhaps even replace it.