94 9000 engine racing problem

For the past 12 months I have been having a problem with my engine racing. Here are the specific symptoms:

  • Approximately every other week, after running for 10+ minutes, the engine will suddenly start racing.
  • It will rise from 1k rpm to 3k. Often it will then surge from 1k to
3k every second or two.
  • If I accelerate, sometimes the engine RPM will rise but then not fall for a while when I take my foot off the gas. If I turn the car off for a minute or so and then restart it, the problem will disappear.

I took it to two local SAAB dealers. One replaced the IAC-that didn't fix it. The other suggested a new ECU / computer for the engine-- I picked up a used one but that didn't fix it either. That same dealer then told me it was a "known and unsolvable problem" with Saabs and was related to the fact that I was the only driver of the car and I didn't vary my driving style enough-- this didn't make any sense to me! Does anyone have any ideas here? I'm at my wits end!

Reply to
dyerparts
Loading thread data ...

"BMWs have the same problem, Sir..." "Do your wife sometimes drive the car?..."

Almost certainly a vacuum leak. It could be a hose with a split end, the split may be hidden from view. Listen for whistling noises in the engine bay.

Reply to
Johannes H Andersen

Thanks.

I had the same thought, and pushed the dealer to check that. They seemed to poo poo that idea-- not sure why. If the problem is intermittent, do you think I would still hear the whistling noise all the time?

Reply to
dyerparts

No, you should hear it when the engine races at idle. Whistling noise is perhaps not the best description, it may be a faint unusual noise of rushing air if you know what I mean. However, it bothers me if the phenomenon is intermittent. You could also try to check the plug connection to the air mass meter.

Reply to
Johannes H Andersen

I had a similar problem with a Vauxhall Cavalier ( my last non-Saab car ).

Engine would take it into its own mind to 'rev up' - often when declutching before a junction. Sometimes on start-up.

It seemed to stop when I repaired a well-hidden leak(s) in the rubber hose feeding the inlet manifold from the air filter. Low revs rough running also ceased. ( Bosch Motronic ECU btw ).

I concur with the above.

Graham

Reply to
Pooh Bear

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.