I would suggest your indy take a look at the motor mounts - cars shaking at idle almost always point to a deteriorated motor mount.

Now why does the engine RPM dip below normal and then come back up? One reason I can think of os the transmission not coming out of lock-up (this normally occurs when you are coasting down off load) and the engine gets lugged down and then the tranny unlocks the torque convertor and RPMs return to normal.

Without looking/driving your car I am only guessing, but these are 2 things I would check out. It might just have a sticky throttle plate and only need some Gumout carb cleaner squirted down the intake to clean things up.

John in San Antonio

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John Hughes, was in Landstuhl, Germany but currently in San Antonio, TX


1978 280CE Astral Silver now 59,xxx miles and counting "Silber-Kugel"
1986 300E Black Pearl Metallic 143,xxx miles 5-spd daily driver w/ blk leather "Schwarz-Schönheit"
1989 190E 2.6 (euro) 5-spd Desert Taupe 112,xxx kms Had to leave behind in Germany!!! "Helga"
1983 300D Pastel Beige now 312,xxx + miles SOLD

OBK#24