My 1995 volvo 960 with about 125k miles has intermittent issues with the fuel gauge. It will display a higher level of gas than what is actually in the tank. Usually somewhere around 1/2-3/4 when there probably is more like a 1/4 remaining in the tank. I think this usually happens when it is warmer outside.

Last year the car had a bad hose that went to the gas tank and the auto shop had to drop the tank to fix it. A few months later I noticed the errant fuel gauge.

Today I finally had a chance to take a peek at the gas tank through the opening in the trunk and didn't notice anything out of the ordinary but I am not really familiar with this part of the car. Does anyone have any ideas what might be causing this problem?

 

the sending unit might be a little gummed up? Mine was kind of acting the same way for a while, and I ended up dumping some techron cleaner in that was supposed to get rid of any buildup. It seems to have worked, for the gauge has been fine for the last 2 years