My '89 9000T has started hesitating, by which in this case I mean that I've had several instances now where at low speed, say 25mph, I want to speed up but applying the pedal doesn't increase the revs at all. In fact the revs I still have aren't powering the car forward. So for a few seconds I'm just rolling as if in neutral, then something 'catches' and the motor revs up. It feels like the car is about to stall completely, but it doesn't quite do that.
After the first couple of instances I did some web research and found one thing I could do myself right away. The idea was to get off premium gas (I usually run 92 octane). I had room for only about 6 gallons, so I added that in 89 octane. It happened again anyway. I then took it to a knowledgeable SAAB mechanic (Ryan's in Northampton, MA) and of course they couldn't get the symptom to appear on a test drive. Nevertheless they found a failed turbo bypass (hooter) valve, replaced it, and cleaned the throttle plate.
For a few days after that, maybe just 75 miles, it didn't happen. Then last Sunday it happened as I was exiting a turnpike tollbooth (after running at 85mph for an hour). Since then it happens every time I take the car out, within as little as 100 yards, up to as far as 2 miles. So it's not a running hot symptom. These last few instances have been not quite as alarming as the first three, lasting maybe 3 seconds instead of the previous 6 seconds. I now have another appointment at Ryan's on Monday.
Meanwhile, any guru ideas?