73' 350SL Cold Idle Surge - Mercedes-Benz Forum

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post #1 of 3 (permalink) Old 12-19-2010, 09:31 PM Thread Starter
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73' 350SL Cold Idle Surge

I have a 73' 350SL (3.5 gray market) that has always surged at idle cold, then smooth warm. Aux. air valve is functioning creating high idle, then it lopes or surges like its lean. Checked coolant sensor - ok. Don't know what else it can be. Help
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post #2 of 3 (permalink) Old 12-19-2010, 11:32 PM
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I had the same issue with my 4.5. I replaced all the vacuum lines and solved the issue... Those plastic lines are available at a local parts store. If you go down this route, be sure to replace the rubber connector bits as well. They often crack with age.
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post #3 of 3 (permalink) Old 12-20-2010, 06:48 PM
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Also, make sure that the throttle position sensor is functioning properly. You should be able to hear it click when the throttle is released from a very slight opening.
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