experiencing intermittent problems w/ fuel gauge. Been told that it might be a sensor in the fuel pump and cost around $700 to replace. Is this a common problem? Is there a problem if I continue to drive vehicle?

 

most likely it is the gauge on the sending unit causing the problem. To replace this you need to replace the whole fuel pump module. As long as you know how much gas is in your vehicle and keep track of it you should be okay. Other wise you'll be walking to the gas station.

 

You didn't say whether your Sebring was a coupe or convertible. If it's a coupe, it's an easier replacement. If a convertible, it requires dropping the fuel tank out.
For $700, I think I'd make it a point to fill up every couple hundred miles.