So, driving home from work on Friday I had two things happen.....

First, the accelerator pedal broke which made it very difficult to drive. But add to that when I got home and backed into my spot, the car was idling very rough.....so rough that I thought it would die. My rear view mirror was rattling so bad that you couldn't tell if anything was behind you.

This is happening with, or without, the AC running. Very very strange...

Anyone got any idea why this would happen in the span of a 1 hour drive home?

Once you give it some pedal and get to about 800 to 900 RPM, it smooths right out, but with a 550-600RPM idle, yipes.

Any suggestions on correcting this, or where to look for problems, is greatly appreciated!

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1998 W202 C230 - The money pit of late.
1984 W126 300SD (356,800 miles) Gone to the wrenchapart
1984 W123 300D Gone to the wrenchapart
1972 W108 280SE 3.5 (sold but not forgotten)
1986 Buick Grand National 3.8l Turbo (86k miles)
1966 Glassic Model 'A' Replica http://www.glassicannex.org

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IIRC the correct idle is 750-800 so their might be an issue

perhaps an injector is not firing correctly or not at all. fuel starving? cover the basics ya know

You said the accelerator pedal broke. Please explain more about what part broke and how it broke. The two problems you describe may be related. You may have a linkage problem.

TimK

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EPA 609 & 608 HVAC Certified
_________________________________________
83' 300D Turbo - 300K + Miles
00' 1.9L TDI Beetle
85' 6.5L Turbo, GV-OD, GMC Suburban,
67' 2.5L Diesel NA - Land Rover Series IIA

Here's what you do if it's so cold your diesel fuel gels. Smear some on some toast and stay inside until it warms up outside.

My SD also has a case of the shakes. Someone here suggested cleaning vales, thinking IP valves. May try tomorrow, not too time consuming, yet have recently done a purge. Did not shake during purge, will have to check condition of lines near tank, if a problem there, would be a leak? All new lines, clamps and filters under hood.

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83 SD

84 CD

too much resistance on the linkage = broken pedal and not a high enough rpm at idle?

I'd grease all the ball joints in the linkage and at the fire wall - worth a shot?

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~shell
As of 2/2010:
2001 CLK55 0o\=*=/o0
13.6 @ 106mph
10K mi
1984 300SD
260K mi and going and going...
97 S600
46K miles
1991 Sentra SE-R (extremely dorked with)
www.se-r.net

Could the engine be loping? Check on your rack dampener bolt, it may have worn out or come out just a little bit, which would cause huge shakes.

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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car

How are your engine mounts and shocks? When I bought my car, the lower bolts on both engine shocks were missing. Believe me, that leads to the engine doing the idle mamba...

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"I have no convictions ... I blow with the wind, and the prevailing wind happens to be from Vichy"

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'97 Jeep ZJ Laredo
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If the rough idle occured as soon as the linkage broke the chances are strong that somhow they are related. Two failures at the same time are not common. Perhaps the result as mentioned is a case of you restoring the linkage with a lower idle than before as already suggested. Thats also where I might go.

Thanks for all the replies folks.....I think I may have discovered the cause last night...and some of you have hit upon it....

With the hood open, I pulled the "STOP" lever away from the valve cover and the rpm's increased just a bit and everything seemed to settle down.

So...now I have to figure out how to keep it there.

The pedal has a round ball connected to it, which slides over the bar from the engine bay. The ball broke off the pedal (again) and stepping on the pedal was like stepping on a brick...it did nothing.

Guess I have some work to do, adjusting and lubing all those connections...then checking the rack dampener (do I have to have my wife in the car for that?????)

Finally, the motor mounts are solid, so no worries there.

Thanks again ya'll ! !

__________________
1998 W202 C230 - The money pit of late.
1984 W126 300SD (356,800 miles) Gone to the wrenchapart
1984 W123 300D Gone to the wrenchapart
1972 W108 280SE 3.5 (sold but not forgotten)
1986 Buick Grand National 3.8l Turbo (86k miles)
1966 Glassic Model 'A' Replica http://www.glassicannex.org

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