You guys must know the answer to this one -- when my 400E is cold, the idle surges up and down, like the car is about to choke and the RPMs shoot up to compensate. If I'm at a stoplight like this, the car fights against the gas pedal when the RPMs surge. Once warmed up, the idle is fine. What needs fixing?
The "slide valve" MBZ's fancy way of saying throttle body. Sounds like yours is beginning to fail.I have known several 400E's that have had to replace this. This is the part that sits under the airflow meter (hot wire). Removal requires taking apart the two piece intake manifold. Have the control unit scanned with the MBZ STAR diagnostic computer first to check the trouble code/codes.
Also take a good close look at your entire wiring harness. Most M119 engines with over 100K miles usually have this replaced at the same time. These services are not inexpensive. Good Luck..
Some good reading...
Check out the engine start specs.
http://mb.braingears.com/124_DISC1/Program/Engine/LHIS/07.4-0030.pdf
http://mb.braingears.com/124_DISC1/Program/Engine/LHIS/30-0010.pdf
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Chuck "You can't kill em"
'74 240D - 359,000 Miles (sold) • '76 300D - 350,000 Miles (sold)
'84 300CD- 280,000 Miles (sold) • '85 300D - 380,000 Miles (sold)
'87 300D - 275,000+ Miles • '87 300D - 175,000+ Miles (yes I have two)
'98 G320 - 150,000+ Miles (Official Range Rover Recovery Vehicle)
sorry -- i don't remember... i no longer have the car, so i can't go back to look through my records. i know it had a faulty stoplight switch and some fuses by the firewall shorted out too, but i can't remember if either of those things had anything to do with the idle.
Linear Mode
