The gas gage on my 2003 Chevy Cavalier stopped working today-I filled up just shy of full yesterday-no problem. Today I turned it on and the needle went to F and stayed that way, even after 130 miles. Once it suddenly went to E and the check gages light showed. I pulled over, turned of the moter and then turned it on and once again it went to full. What is causing this?

First I'll ask, do all the dash lights come on when the ignition is turned on? If not, fix the ignition switch first, if they do come on then I'm afraid the stepper motors on your instrument cluster have gone haywire, there are several repair kits for these stepper motor malfunctions available pretty cheap

You need to take it to a shop you have an electrical issue.

weird...first thing to do is get a scanner hooked up to see what caused the check engine light-free, at pretty much any retail auto parts operation-i wouldn't get overly concerned with the gas gauge right now, teh code that tripped the check engine light might explain that problem.

One fuse operates all the gages, so no the fuse is not the problem, the problem is that the gas gage sending unit (a variable resistor) that senses the level of fuel in the gas tank is defective and needs to be replaced, this is the most common problem with any fuel gage problem

The blinking light is telling you that you have a headlight out, if you look the service light should be coming on when the light stops blinking.
Replace the head light and all should be fine.

Most of the time the level sensor in side of the fuel tank is the problem. I'd say 1 out of 10 the cluster is bad. But with the way you say it was acting up before hand I'd put my money on the level sensor and not the cluster. The fuel tank will need to come out of the car to fix this. There is not access door to the fuel pump.

The fuel pump as a gage sender that monitors the gage in the dash. I would replace the fuel pump .
Very common problem

Good Luck

yeah it could be full of water in the gas you bought. see if you can pull a sample and check. start looking at the filters.

Unfortunately this is most likely the fuel pump module, which includes the fuel level sensor also. This should be diagnosed more thoroughly with a scanner, a good scanner will be able to check instrument cluster separately to confirm the gage is working right,and check for trouble codes that may not light any warning lamps. Hope this helps. Rate me please.P.S. Dont use that fuel station any more.

Yes it is all one unit, and yes that is what the problem is. don't use aftermarket parts, use OEM, (Delco Remy) they are much better quality.