Pontiac Repair: fuel gauge, fuel level sensor, grand prix gtp

Question
I have a 99 grand prix gtp with a 3.8 My fuel guage flucuates while driving and when I put in neutral it drops all the way to empty and when I put it in drive it goes to full I also only get 14 miles per gallon

Answer
Hi Kraig:

Chnaces are that the fuel level sensor has gone bad on the fuel pump module. The terminals on the level sesnor wear out and cause exactly what you have said is happening to your car. Get the part from a dealer not aftermarket! while you are there get a bottle of fuel system treatment. there is one that has a protectant for the level sensor it says it right on the bottle make sure you get thye right one. follow the directions on the back of the bottle as to how much to add to a tank and use it a couple of times a year. The stuff works great!!!!