My SL320 gave me the same code, it was a loose vacuum line right at the valve. It was an easy fix, I just inspected each line, removed it, made sure there were no cracks or loose connections, replaced a rubber connector between the valve and the plastic line to the manifold and that fixed it. Regarding your rattling when revving, that sounds like a chain or tensioner. Mine did that when you would rev it up, as it went back down to idle, it was a tensioner on the chain, an easy fix as it was the upper one. I am told the chains on the inline engines last a long time because they are shorter and tend to not stretch as much, but the tensioners can be a little troublesome. Get your code fixed, and then try to locate the rattle in your engine. The idle problem you are having can be related to a vacuum loss as the ETA tries to compensate. (Purge Valve?) Good luck!
B

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Brian W. Heitman

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