I have a 2002 C-5. My ? is. When I fill the fuel tank the gauge reads full but the heads up display shows only 1/2 full. I was told different makes of fuel and octane levels can affect the sending unit. I only use only Sunoco 260 and Speedway Hi test. The problem just started recently as I've been using both makes since the car was new. Any input will be appreciated.

LMan

 

In the February issue of Corvette Fever a reader letter said that:
"A simple solution is to change to Chevron, BP, or Shell gasoline. The additives in these gasolines work to clean the fuel-sending unit. Thousands of Corvette Forum members have tried this simple method to correct the issue referenced. To my knowledge, it has worked 100 percent of the time."
I havn't tried switching fuel yet so I don't know if it will work, but it doesn't hurt to try.

 

GM has a whole plethera of update reflashes on the PCM on all their vehicles. If I have time, I can check TSB's on that to see if there is a correction. Sometimes, they don't even post those corrections until you do the reflash and see what it corrects. You might check with your GM dealer about any updates available for your car, kinda like updateing your video drivers or sound card drivers on your computer. The instrument panel is controlled by the Body Control Module and there might be a body control code that you can only access with a scan tool.

 

Thanks. I also read Shell gas can correct the problem. Also read a new fuel additive 4K made by BG will correct it. Thanks again.

LMan

 

Good new's. The problem has corrected itself. One of 2 things helped fix it, or the combination of both. The fuel additive from ACI. Or the good advice from this forum. I filled the tank with Shell premium after using 1/4 of tank it was fixed.

L-Man