I've come to believe that a "24 hour" rule exists on my Volvo. It's like I make an adjustment and I don't notice anything. 24 hours later, I start the car and the changes take effect.
One example is my idle. I think I am fighting pinhole vacuum leaks and I am trying to isolate them - but here's the deal. I've cleaned my throttle body & IAC and she idles well under the circumstances. But, when I turn the black knob under the throttle body - it doesn't affect the idle - until later in the day when I restart the car, or 24 hours later. By 24 hours I generally mean I let the car sit until the next day.
Anyway - let's say my car is idling at about 600 rpm. I open the knob
1/2 turn, then another and another and another and 2-3 turns later the engine is idling exactly the same.I shut the car off, come back a few hours later, or the next day and the idle is up according to the turns.
Why the delay?
Thanks!