My 81 240 is idling poorly, getting poor mileage, and is exceedingly gutless. I have found and repaired several vacuum leaks. This has improved the situation. I suspect there are others that I haven't found yet. I am deeply suspicious of a little gizmo on the top of the fire wall near the wiper motor. It has a vacuum tube goin into it nd a wire coming out of it. It seems to be making a hissing sound when the car is running. If I unplug the tube while the car is running the engine dies. Can anyone tell me what this thing is so I don't look like a jerk when I go looking for a new one? Thanks in advance.

Matt Gould
New amateur volvo mechanic

If your car has A/C it could be an idle control valve that allows the engine to rev up when the A/C is engaged. Try to pinch that hose so you can stop the air leak and see if the car idles better. If it does then that component is where your leak is. If you have no A/C you can plug up that line and do away with that component. If the idle does not change when you plug it/pinch it off then your leak may be somewhere else. Good Luck!

Sincerely,
--
Julio Meza

1979 264GL B27F 127K --> BW55->M46, CLS, IPD Sway, 81+ Dash, Gauges, Flat Hood & E-Codes

1979 262C B27F 163K --> Restoration Project

1984 245DL 216K --> Sport Wagon

2002 Mercedes C320S 33K --> Wifemobile