EHA is Elctro-Hydralic Actuator. It is mounted on the side of the fuel distributor. This is really what adjusts the pressure to adjust the mixture. The Idle Air Control Valve is what raises and lowers idle by allowing less or more air into the intake bypassing the AFM, Air Flow Meter, and going directly to the throttle body. It opens and closes to adjust air flow. It is in between the last two intake runners under the air box. The Cold Start Valve is the only electronic Injector there is. When cold, below 60 degrees, this fires a burst of fuel into the intake manifold to assist in cold starts. Only fires once before starting. Then you have all the electonics that work this crap. You have that temp sensor which tells the CIS-E controller to fire the cold start and also cycle the Idle Air Control Valve as well as the EHA control. As the engine warms the EHA leans the mixture, and en-richens when cold. You issue may be the cold start valve needs cleaning as well as the Idle Air Control Valve needs cleaning. The Idle Air Control Valve also could be shot, or your switch on the throttle linkage could be bad as well. The switch on the linkage lets the IACV know when you are not on the gas and thus Idling, which is the only time the IACV is actually doing anything.

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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.....