I have a trouble code P0442

That code is for a small leak in the evaporative emission system. A loose gas cap typically sets a code for a large leak. There are dozens of other things that can cause a leak and they are almost impossible to find without a smoke machine. They put out a white non-toxic smoke at 2 psi. You inject that into the system, then watch for where it sneaks out. Since the leak involves fuel vapor, you can't find it by looking for a wet area. The typical culprits are cracked and dry-rotted rubber hoses and loose hose clamps, but there are also valves in the system that control the flow of those vapors into the engine.