[scallywag]

Hello everyone,

I have got an idle problem with my Saab 9000 CSE 1993 2.0 (non-turbo). Basically I have got two problems that probably are due to one fault.

1) When idling after the engine has warmed up, especially when sitting in traffic, the engine idles nicely at around 1000rpm, but about every 30 seconds or so the engine drops the revs almost to the point of stalling and then brings it back up to the 1000.

2) I also have a random "Check Engine" light . This comes on randomly and does not seem to match the above problem and I cannot get the error code (flashes) out of the ECU because its so random when it appears.

I posted a while ago about the Check Engine light and someone suggested the IAC valve. I thought this could be the problem for both faults so I gave it a clean and a lubrication but it has not made any difference, Im not sure if it needs replacing. Does anyone have any idea what could cause this because I dont wany to buy a new IAC, if it turns out to be something else. Could it be a faulty sensor somewhere? Any help would be very greatfully recieved.

 

[StephenA]

Check for any holes in any of the pipes round the engine.

Have you tried a good dose of injector cleaner - it often makes a great difference.

Steve

 

[Deester]

Hi Scallywag,
I'm still having problem 1 with my '97 LPT, it's under warranty (luckily) at the moment, so far it's had a new IAC valve, DI cassette, throttle chamber has been cleaned, but the problem persists. It's worse when the engine's warm but does it from cold occasionally. It's only caused the engine to stall once but it's an annoying fault. Can any experts suggest what else might be the cause (if it was a hose it would be a persistent fault?).
Cheers, Leo.

 

[scallywag]

Leo,

Thanks for that, it souds like replacing my IAC wont help much. My guess is that it could be a faulty sensor somewhere or something like that but we will see. I will get to the bottom of it eventually. Let me know if you manage to get it solved under warranty.

 

[anarkietown]

Hey Scallywag--

I've had a similar problem with my 1990 9000i auto. It would idle too fast at cold start, and when I came to a stop, the revs would drop, nearly to the point of stalling. I had the Idle air controller valve cleaned out, and it fixed the "nearly stalling" problem for a week...

However, after that, it did the same sort of thing again. Yesterday, I finally had enough of it, and went to a different mechanic, who cleaned out the throttle body and butterfly valve, but noticed something else was askew. Apparently, the throttle stop screw was incorrectly set, putting the throttle control out of synch with the engine management computer. Thus, the engine behaved somewhat erratically.

After he reset the throttle screw, cleaned the throttle body and valve, the car ran beautifully! At first, the idle revs would jump a bit (from about 900 to 500 and back) at idle, but nowhere near as dramatic as before. Today, however, when I drove my car, it ran perfectly. The throttle response was better, the gear shifts were more precise, and it actually felt like my car had more power (this is just my subjective opinion though!).

I hope my experience helps you, but remember, I'm not a mechanic, just a Saab enthusiast-- after all, I could be wrong... But, it might help having a qualified mechanic inspect the throttle screw or throttle body.

cheers,

Rocky