this truck has a hard time restarting after the engine has warmed up and sat in a parking lot. it will restart but after two or three tries. i thaught it was vapor locking, so i removed air cleaner and all tubing to insulate, and found a device on the back of the motor broken. it is conneted with a cross over tube between the back of the heads, and has a rubber hose off the top. i have the chiltons manual and have found this device but no discription of it. please help me. thanks rich.