Hey Everyone,

My '81 240 GL is acting kinda weird just of late. It has a B23E Engine w/ K-jet (CIS). This is a Canadian model that has the Pulse Air EGR system. I recently had some idling problems but they were rectified when I replaced the larger of the two vacuum hoses that runs into the back of the throttle body from the carbon canister.

Since then the car has been running quite good and idling at about 900 - 1000 at all times, even when starting in colder weather (i.e. below freezing). Now something weird's going on. Sometimes after warming up the idle is suddenly jumping up to 1500 - 2000 rpm and won't go back down no matter what you do unless you shut the car off, wait a couple minutes and start it up again. (I haven't tried starting it up right away so I don't know for sure if that would work too.) Most of the time it will idle back down where it's supposed to after restarting it.

I recently replaced my aux air valve (air slide valve) with a good used one and it seems to be working fine. At any rate it doesn't make sense that valve would suddenly open up again after the car has warmed up and the valve has closed off.

I checked the Haynes manual for possible reasons for fast idle and it listed sticky throttle plate, sticky throttle cable and a faulty idle air control valve. Well, I'm pretty darn sure it's not the throttle cable that's causing the problems. What is the idle air control valve ? Do I have one of those on my k-jet system ? (The Haynes book covers all the different types of FI systems used in the 240 so that may not apply to my car.) If so, where is it and how do I test it ?

Anybody had a similar problem with their CIS system and/or have a good idea what the source of the problem is and/or how to diagnose it ?

Thanks,

Roger