1994-2002 [Subscribe to Daily Digest] |
The O2 sensor normally lasts much longer, thanks to the 3 wire heated design. I don't think that the O2 sensor would cause a fast idle, but it could throw a CEL, check engine light. Check fuses for O2 sensor.
The ECU might be struggling with another problem such as plugs, dirty injectors or a fouled throttle body. So doing some PM on these items first if they may have been neglected, would be a good thing to do in any case. These things can then be eliminated as root causes if that fails.
The Motronic ECU might also be subject to a recall. They can read the ECU's rom version and see if you qualify for a replacement.
The throttle body is easily swabbed clean with some solvent and a cloth, with the throttle held open. You don't need to flood the thing with 'carb cleaner'. You will need to figure out how to remove the plastic resonance chamber from the top side first.
Check that the battery is ok, remove top caps and add distilled water if needed. Yes, battery broblems can make ECU's act bad.
If the fuel filter was bad, you would feel it as an inability to deliver power at high throttle and RPM's long before idle would be affected.
Some have this problem and have focused on the idle air control valve. This is expensive, so other items should be addressed first, especially if they are of a preventive maintenance type. The idle air control valve could be removed and flushed with a mild solvent. Note that some folks have replaced this part without solving the problem.
Fast idle could also be caused by a split vacuum hose, so locate the beasts and check that they are not split where they are stretched to fit over hose barbs. If you need new hose, you can get it at auto shops or Ace Hardware.
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.