i have a 2000 chevrolet impala ls and the gas gauge is okay before i start the car, but after it is started the gauge rise up and down and float to full, only if i have 1/4 tank of gas. what can i do to correct this promblem ?

get a NEW battery...wirebrush the 1/0 battery cable down at the end where it connects to the chassis....wirebrush the chassis where the lug bolts to it....to assure 300 cold cranking potential and a source ground that isn't varying in amperages and voltages....you know they used to have a special voltage regulator to absorb these things back in the day~

there is a slight chance that your Float ain't floatin' no more...too~

Clearly the problem lies in the grounding of the tank...a renewed chassis ground should correct this budda bing budda bam~

the sending unit in the tank is bad some times these can be bought seperate and sometimes the whole fuel pump assembly has to b bought , very common in 1/2 ton trucks and suvs of that model or body style ! could also b your gauge cluster chevy had lots of problems with those

I have a similar problem in my 2005 Buick Terraza. I had it diagnosed as a sending unit in the gas tank, which the dealer wanted $750 to remove the tank and put in a new one. I just now go by miles driven and never trust the gauge. When I fill it, it will go to empty and the idiot light will come on. GM now charges $125 to check what the idiot light and check motor light means. Screw them, I refill after 325 miles of in town driving, 400 of total highway driving. The gauge will work when 1/8 of the tank is gone. I tried not filling it up, but the gauge still acted up. If you can check all the ground wires, made sure you have a good connection and it still acts up, and if you can drop the tank, (empty it and blow air into it go rid it of the gas fumes) and replace the sending unit yourself, you may save $700+ for the fix.

have anybody experiencing a gas tank blowing up while the car is pop

Correct your question. Do you mean in park? Only will it blow if there is flames near or in it and gas fumes. If you have a electric fuel pump inside and it shorts out, it may cause an explosion. Any electrical spark may ignite the gas fumes inside a closed container if there is oxygen available to complete the chain necessary for ignition. Don't weld, cut or use a match to look inside a gas tank without first making sure ALL the gas and fumes are gone.

Don't smoke...it's bad~

:-)