You will need to make certain that no vacuum leaks exist to start with. The Aux air needs to be removed and placed in a pan of hot water ( appox 150F + or - 10F ) for about 5 min. The air passage should be closed ( should not be able to blow thru it ),if you can the valve is bad. If the valve is good. Start by backing off the throttle stop then adjust the screw untill it makes contact plus a quarter turn, tighten down the locking nut. The throttle sensor will have to adjusted next, rotate the throttle sensor fully clockwise then with a volt meter attach the leads to two of the prongs and adjust the throttle sensor counter-colckwise till the risistance drop to zero. tighten the locking screws that secure the sensor. Adjust the idle mixture screw after the engine is at normal operating temp. Set the idle at 800 to 1000 RPM. If for some reason the idle is still too high after starting a cold engine, put something that will restrict air flow in one of the hoses to the air valve.


I did this to my 73 and now the idle is a little faster after start up (cold engine) and drops to around 800 after warmup. You have to experament a little as to how much restriction your Volvo will need in order to idle at an RPM that you can live with. Good Luck