I have had this '91 240 since February and it has never idled well. The car starts fine but will not idle worth a hang for the first say five minutes of the drive, then idles ok, but not smoothly. Once you stop, if you don''t ease it into park, the car dies and that is the only time you get the Check Engine light which goes away once you start it again. A couple of months ago I checked the codes and received a 1-1-1. Last night was a 2-3-2 which is indicated as rich mixture compensation. The car had a tune up in March. Any thoughts...?

Thanks gentlemen...didn't get to anything until the weekend. Right after I bought the car, I didn't have a lot of time for investigations and the idle issue was there so one of the two best Volvo mechanics in town replaced the idle control valve so I headed into the throttle body, which wasn't that gunked up so I was suspect that would fix it...got it back on the was digging around by the idle valve...and found the hose from the valve to the injector side of the throttle was kinked like a garden hose....waaaay too long. I started the car and unkinked the hose and the idle, of course surged. It was too hot down there and was tired of messing with it so Chapter II tomorrow (had spent most of the day on a date with control arm bushings).

When was the last time the throttle body and idle air control valve was cleaned?
Dan

Check your throttle position switch - pop off the intake bellows and *just* push on the butterfly. Should *click* at the slight motion. While you're there - is it nasty in there? Remove and clean. Causes rough idle.

OBD mode 3 lets you check the idle air control. Listen for a vigorous click-click after it cycles the injectors.

Get a Bentley book. Really.