yes it does have dual tanks and that makes sense how do i fix that also the tank i don't use fuel gauge doesn't work

 

First you need to determine if cross-flow is the problem. Not having a working rear fuel gauge is going to add a little more effort. Does the truck run on the rear tank? If so you could run on it until it runs out. Which could cause other issues.

You could use a piece of wire to use as a dipstick to measure how much is in the rear tank. Drive for a while then remeasure.

If the rear tank is filing up that means the check valve is bad in the rear Fuel Delivery Module (FDM). You need to replace the entire FDM to resolve the issue.

If both tanks are filing each other then you may have a bad fuel pressure regulator which is allowing too much pressure to be applied to the injectors and the check valves. Too high pressure will cause the check valves to leak. Best bet here is to check the fuel pressure.