my gas gauge fluctuates really bad these days.
if i fill the tank more then 1/2 full it goes wackojacko.... like max full to 1/2 and back again then jiggly jiggly. i figure its fuel sender time, i did add some Chevron Techron Concentrate Plus, it said it can help this problem, but it didnt......
the cars always had a funky gauge like never going all the way to full (almost but not all the way).
now i did swap to a tach gauge cluster a few mths ago, no idea if thats the problem or not, it came out of a 97 montecarlo my lumina is a 98 base.
i found this .
GM has just issued a TSB
on this problem that applies to ALL GM vehicles and
blames the high incidence of sending unit failures
on high levels of sulfur in gasoline. The sulfur
corrodes the sliding resistor mechanism and
produces erratic and inaccurate gauge readings. To
address this problem, GM has released a FUEL
According to GM TSB #06-00-89-07BB, you should
purchase a bottle of GM Fuel System Treatment
Plus (part #88861011 for GM brand, 88861013 for
AC Delco brand, and 88861012 in Canada) and add
it to your tank at every oil change. The additive
cleans the sulfur corrosion from the sending unit
and prevents new corrosion by laying down a
protective film. The additive also removes engine
the gm stuff is like $30 ?? way to much , so i went with the chevron additive. Obviously it didnt work... got it at pepboys on sale for $5.