High, Inconsistent Idle in 1989 SAAB 900

Some of you may recall my earlier thread about buying a 1989 SAAB 900. Well, I bought it. I spent last night replacing the shoddy vacuum lines and tried to ensure all the seals were tight around all the valves. I’ll have to double-check but everything appeared to be a lot more secure and a lot better overall. Just to be sure, I checked to see if there were any other loose connections and I didn’t see anything outstanding, though I can always re-check.

After that, I tried to start it again to take it for a drive. The hard-starting issue seemed to be slightly better, but it still required about 5 or 6 seconds of cranking while using the gas to get it to start. The guy who sold it to me set the idle screw so the idle was around 2k RPM so I could get it home. So while it was idling, I adjusted that first and got it to around 1,000-1,100RPM since anything less seemed to cause it to stutter or bog down.

Once it seemed pretty consistent, I took it for a drive and drove pretty well, though there was some hesitation remaining if you didn’t use enough gas before upshifting, especially into 2nd gear. The strangest part was at one point, it did bog out and I had to restart it. After that point, the idle seemed high and stuck around 2k RPM and there was more vibration coming from the steering column, so I took it home.

When I got home, the 2k RPM idle remained and I noticed that the temperature gauge was 3/4 up. Before I turned it off, I tried one more time to adjust the idle but there was no change, whether I tightened or loosened the screw. At that point, I just turned the car off.

At this point, I’m wondering if my problem is a sticking AIC-Adaptive Idle Control valve or a faulty coolant temperature sensor or possibly a stuck injector. Beyond that I can only imagine I overlooked a vacuum leak somewhere. Thanks for reading my novel, I appreciate your input, guys.

The best thing you can do, since you obviously plan to keep this car, is buy a factory service manual. A factory manual will tell you what you need to know about idle speed, vacuum hoses, and everything else on your Saab.

Try Books4Cars.com for a used manual, which will be much less expensive than a new one, but get a factory manual. You’re going to need one.

Ok, I’ll look for one. I guess it’s not enough that I’ve got the original owner’s manual and other docs, eh?

Not if you’re serious about it. Service manuals are worth their weight in gold.

I’ll get right on it, then. Beyond that, any guess on what I’m looking at here? I don’t mind doing my own wrenching or buying the parts, I just don’t want to throw money where it doesn’t need to be thrown.