Fluctuating gas gage

I have a 2000 Park Avenue and the gas gage jumps from full to empty once the gage reaches 1/2 full. What is causing this and what would be the approximate labor involved in repairing?

I would buy a Scangauge II and it will give you a good read out of how much gas you have in the tank once it is calibrated for your car.

I have a 2000 Park Avenue and the gas gage jumps from full to empty once the gage reaches 1/2 full. What is causing this and what would be the approximate labor involved in repairing?

Most likely the fuel sending unit is sticking/malfunctioning. There is an access hole in the trunk for this. It is called an electric fuel assembly since the fuel pump and sending unit are in one whole unit. This part runs about $250-$300 from Advance Auto parts, more for the dealer's AC Delco part. I would guess labor to be in the order of a few hours, maybe a few hundred dollars, but that depends. Price will vary business to business and area to area.

Only qualified/experienced people should be working on the fuel system. To be sure before spending the money, it may be wise to have the repair shop diagnose it for you. If you were to bring it in and have a fuel pump/sending unit just blindly replaced and it didn't cure your problem, then you are out $$. If you have them diagnose it and they say you need a fuel assembly, then it should be guaranteed or they'd have to keep fixing. Either way, it'd be best to test the old one first and make sure. Blind and random parts replacement can become very expensive.

Good luck.

Yeah the same case exists for my 97. When I got the car the gauge was spot on until is reached about half a tank. After that, the needle would move randomly like it was possessed. One day it got so excited it spun past the piece that comes out from the dash after the "F." Since it spun past it, it isn't able to work. I was told that the issues concerning my fuel system and gauge dealt with what was mentioned above. I've decided not to fix it since I have other electronic gauges for measuring my fuel. Good conversation starter though, ha. Good luck.

DH

I got my Scangauge II from Mod bargains

Mod bargains has it for 159.95
Use coupon code "scan" to save an additional $20 for a total of 139.95 with free ground shipping to your door and no sales tax.

http://www.modbargains.com/product.aspx?pf_id=ScanGauge_MW

The fuel level sending unit itself can be replaced DIY following proper safety procedures. Many AF members including myself have done it. You do not need to replace the complete fuel pump assembly which is costly. Plus you can check the resistance value and range of the sending unit at the electrical connector at top of the fuel pump assembly with a multimeter (DMM) but the fuel pump assembly should be removed first so you can manually control the float.

Typical cost via certain AC Delco suppliers is around $85 for the fuel level sending unit.

I have performed this job on a few cars. The fuel pump can be replaced solely. The assembly is expensive so you have to weigh the possibilities.

It is my opinion that if my car (currently have a 99 PA) had that issue, I'd replace the whole assembly. It is a costly part. But so is replacing only the sending unit and finding out a week later that the pump decided to crap too. Since it is usually my own labor, I can deal with it. But if you are paying a repair shop, it can get even more expensive than the sending unit alone in the long run.

This is a decision you have to make on your financial situation, condition of the vehicle, whether it's worth it or not. Money always plays a factor. So, if your a DIY-er, you can try just the sending unit.