I know it’s summer but I have time now to work on it. Not so much in the winter. Last winter as the temp would drop down below say low 30s our 240d would only shut off with the emergency shut off under the hood. I checked for vacuum leaks (couldn’t find any) & vacuum (about 25hg). I also replaced most of the rubber vac. fittings last fall. When the temp would get warmer it would have no problem shutting off. What is the possibility the fuel shutoff valve is the problem.