Well, like so many before me,,,,looks like I have to replace my Fuel Sending Unit.  Since day 1 when I bought the car the fuel guage always worked fine until the last half tank....sometimes it would drop from half tank to quarter tank....but not often.

Read a lot about a bladder in the tank.  Is it possible for the sending unit to be fine but when the tank is half full the float gets hung up on the bladder????  Seems odd as I would expect the weight of the gas to keep the bladder pushed against the side of the tank and never interfere with the float....

Thought I would see what you experts think before I buy the part and attempt the swap.

thanks

Reds,

  First of all,   SWEET CE!!!!!!!!!

Now, yes, the neoprene bladder can, and most likely WILL collapse upon itself when the vent hose for the tank becomes clogged. This, I would say would be the most likely culprit.

Regardless of the problem, the tank must come out,The easiest thing to do, and, fortunately this happened to me, is to hope the next time you run out of gas, it happens in the driveway, and you can wheel your baby back in, and drop the tank. The good part is, it will be empty, and not too heavy. Or, you can drain the tank manually, and then drop it. It is not that hard of a job, just take your time.

While you're down there, might as well change the sender, if funding will allow it.

Good luck, and let us know how you managed.

P.S. This information is passed along by me, by the vast knowledge of our beloved Ken Styer, who informed me of this problem when I was thoroughly confused on why I kept running out of gas with 3/4 of a tank showing.

Thanks Ken.

Alan

Ken, your a genious.....great diagnostic tip....Since I just filled the tank, next weekend we will have to take an extended cruise (shucks ) and see if the gauge works down to a 1/4 tank....

Ken, is there an easy way to check if the vent hose/canister are working (not plugged)???

Micki,,,if I have to replace the tank then yes...I don't have any way to raise the back end ....will have the rad replaced at the same time (really wish I were a better home mechanic)

 Sooo... what would cause the fuel gauge, over a period of time, to start registering less gas that is actually in the tank. I have a good 1/4 tank more than what the guage reads. Any thoughts?

 Sooo... what would cause the fuel gauge, over a period of time, to start registering less gas that is actually in the tank. I have a good 1/4 tank more than what the gauge reads. Any thoughts?

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That is one fine looking Corvette, man you have good taste in cars.   

My guess would be old age and corrosion. The gauge works off resistance.

In non FE cars A little Marvel Mystery Oil in the tank occasionally will help with the lubrication and corrosion if that is a problem. My 77 stuck once and an old Corvette guy told me to try it before I pulled mine . No problem since at all.