I have a 92 300E 3.0L with a very frustrating idle surge. The surge only occurs when the car is in gear. If left in park, the idle surge NEVER occurs, and I mean NEVER. I have read several threads on this topic, and have read through the CD several times and I'm still baffled.

Things I have done -
1. I have disconnected the EHA connector thinking the surge would go away. Not so. As before, the car idles perfectly in park, but once put in gear the surge appears again.
2. I have run the car with the O2 sensor disconnected with exactly the same results.

When the surge occurs, the rpm will jump up to around 900 rmp for about 1 second, and then return to normal idle. When you're at a stop light and this does this, it is very disconcerting. Also, if I'm driving on the interstate and take my foot off the gas pedel, the surge also occurs.

Please help!!!! But as I said earlier, the surge NEVER occurs when the car is in PARK.

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92 300E - 116K miles - Sold
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