Most likely a vacuum leak. But also could be a craked AFM Boot! It sits between the AFM and the throttle body. When craked it sucks in outside air and bypasses the AFM plate so fuel is not metered properly. Also check your O2 and basic mixture settings. My 190E had similar issues, vacuum leaks, cracked boot fixed most of my issues when replaced. Also look at your Water Temp Sensor. It tells the CIS-E controller your engine temp so that it can tell the EHA what to do.

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....