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My 1994 940GL with the non-turbo 8 valve motor, Bosch fuel injection has a idle problem when cold.
Temps in the morning are now around 0 degrees C (32 degrees F), and the car starts fine and idles OK, but as soon as it is driven off and stopped at an intersection or whatever, the idle surges between 750rpm and 1000rpm, the oscillations seem to increase in intensity if nothing is done.
I stop the idle oscillations by putting my foot on the accelerator and holding the revs at approx 1000rpm which makes the surging problem go away. As soon as the car has warmed up (middle of temp gauge) the problem goes away and car idles fine at 750rpm. I've never had any idle oscillations with the motor hot.
My car does not have that aluminium hose fitted between the exhaust manifold and the inlet airbox - it rotted away and fell off, so I disconnected the other end and got rid of it. Temps rarely go much below -5 deg C (23 deg F) in Christchurch, so I'm not sure if I really need it. It shouldn't affect idle anyway.
The throttle body is clean, and engine performs fine, hot or cold.
I've looked into the idle air control valve and it looked clean and no sign of oil or gunk.
From reading the 700/900 FAQ narratives, I'm suspecting the idle air control valve. My IACV appears to be one of the later sealed type that can't be opened up and overhauled, and it is expensive to replace, so I'd first like to explore any other suggestions, before throwing money at it. With redundancy looming, I will soon possibly have a lot more time than money...
John Marshall
1994 940GL 161,000km
Christchurch New Zealand
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