Freeing stuck fuel sender float

I have a 1990 Pontiac 6000, it uses the basically the same fuel sending unit as any other GM.

Last summer I used this Bardahls All-U-Need fuel system cleaner. The car was running fine, but I figured Id do some preventative maintenance. After that, my gas gauge wouldnt come down from Full. Starting with the next tank of gas, it would only sometimes work.

All the connections are good. The gauge itself works. The system on this car defaults to Full. What happens is the gauge only sometimes comes down from full. When it does, it never jumps back to indicate a bad electrical connection. It just slowly works its way down to where it should be. It works better when the weather is warm, and when the road is beat up. It comes down a bit with each hard bump. During the extreme cold of the last few months, it never worked. Over the last week since it went up by 50 degrees, it started coming down again. Also one thing that happened once is I filled the tank, but it didnt leave empty until I hit a bump while leaving the parking lot, then it came up to full.

So the only thing that makes sense is the fuel sender float arm is sticking. That Bardahls fuel system cleaner seems to have gooed up the arm pivot. The goo stiffens when it gets cold outside, and softens when it gets warmer, just enough for a beat up road to slowly hammer the arm down.

I was wondering if anyone knows of the best thing I can dump in the tank to free up the arm. Before and during all of this, the car has ran fine. So it must have not gooed up the fuel filter or anything. Awhile ago after asking around, I tried 2 bottles of Chevron Techron, but unfortunately the initial arctic blast hit the day after I filled the tank. Should I try it again? Or is there something better I should try? I know I can drop the tank and clean the sender, but if I can solve this problem without dropping the tank it would be so much easier.

Thanks in advance for any help.

hey my parents have that same car :P

But yeah, I'd try the Techron or Gum-Out with some higher octane again after it gets into the 70's

And remember that you are supposed to put in additive when the tank is as close to empty as you can, then fill it FULL