Inaccurate fuel gage for 97 Millenia S
 

I recently ran out of gas in my Milly S even though the fuel gauge read 1/2 tank. The repair shop said I had bad fuel level senders and that Mazda had a TSB for these. I checked Mazda's TSBs and they don't speak to this particular problem but about the gauge reading empty when there is still 5-10 gallons of fuel left in the tank.

Have any of you Milly owners experienced this same problem? If so was it just a matter of replacing the fuel level sender(s)? How did you determine if one or both were defective? Is this a DIY type of repair? and finally can these senders be purchased from any source besides the Mazda dealer or is that the only option?

Thanks in advance for any feedback you can provide me.