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Discussion Starter · #1 ·
Hello everyone,

I am a new owner of an 2001 SL500. I will try to keep this short, I have been doing lots of reading and research of this model and this is a dream come true for me. It’s 10 years in the making to this day of ownership.

Now the tricky part. I am not too mechanically knowledgeable but I am willing to spend the necessary amount to keep this car in top shape. I have been reading lots in the forum and the amount of knowledge each of you have amazes me greatly.

Upon receiving the vehicle, I begin to bring the car up to date on maintenance. I have reference the factory service intervals on all facets and the following were changed/replaced

1. replaced all fluids (engine oil, transmission, brake and hydraulic top), coolant were kept as the previous owner changed them a year ago.

2. the spark plugs as well as the crank position sensor. Replaced. As I have no record on when they were changed

3. air filter was kept as it was changed last year, cabin filter were replaced, as well as the fuel filter.

4. Brakes (components and parking brake), drive shaft flex disc were inspected and are in good shape. Also the steering lock bolt tightened.

From the detail inspection, we have noticed a slight misfire, after changing the spark plugs, i am still feeling a bit of engine “shake” while car is idle in P. While in gear, the shake is much less noticeable .The rpm is steady while the shakes were happening. Car drives fine otherwise.

I read about possible faults include engine mount, ignition wires and/or vacuum leak. Can someone narrow it down on a likely culprit?

thank you in advance and I look forward to your input.
 

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1995 SL320, SL500, 1998 C280, 2004 E500 4matic
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Cheers!

motor mounts are very plausible, particularly if vibrations are less noticeable in P (no load)

Here is a simple way to “check” for your motor mounts


Regards,
D
 

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Consider cleaning the throttle body with appropriate throttle body cleaner spray. Try a trivial and cheap fix first.
 

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Discussion Starter · #5 ·
Cheers!

motor mounts are very plausible, particularly if vibrations are less noticeable in P (no load)

Here is a simple way to “check” for your motor mounts


Regards,
D
Sorry Dun_Vinci, actually the "shakes" are MORE noticeable while in P.
Looking forward for your input.

Thank you!
 

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1999 SL600 | 2001 SL500 (sold)
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You’re gonna need visual inspection of the engine mounts and transmission mount. How many miles are on your ride anyways?
 

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2000 SL500, 2004 E320
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At 37,000 miles, engine mounts are likely fine but, have them inspected anyway. Unless they are completely shut, fluid gone, I wouldn’t rush to replace them. The likely culprit is vacuum leaks and, if that’s the case, new motor mounts won’t make much difference. But I wouldn’t want to speculate… there are tests that can help to determine if you have vacuum leaks, MAF, injector problem etc…

You say help diagnose so I need to ask… are you willing to actually diagnose this issue, as opposed to speculate?
 

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1990 300sl
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Since it began after you changed the plugs, i would pull them and see if one isn't firing. It should look wet/different from the others. Also make sure all connections to the plugs are good.
 

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1999 SL600 | 2001 SL500 (sold)
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I thought plugs were good for 100k. Btw op which plugs went into the car?
 

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Discussion Starter · #13 ·
Also during the last shop visit the shop cleared the misfire fault codes and found no more misfiring. If I believed the shop is doing a good job then that should eliminate faulty ignition cable right? I was thinking if we can deduce possibilities towards either the engine mount or vacuum leak…
 

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Discussion Starter · #14 ·
Since it began after you changed the plugs, i would pull them and see if one isn't firing. It should look wet/different from the others. Also make sure all connections to the plugs are good.
Hi steelpig, I should elaborate… the shakes were always there. Initially it was diagnosed to be caused by a slight misfiring, found the fault codes on misfiring, then we went ahead and changed the spark plugs, it got slightly better but it’s still experiencing a little bit of the shake when the car is in P.
 

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Discussion Starter · #16 ·
At 37,000 miles, engine mounts are likely fine but, have them inspected anyway. Unless they are completely shut, fluid gone, I wouldn’t rush to replace them. The likely culprit is vacuum leaks and, if that’s the case, new motor mounts won’t make much difference. But I wouldn’t want to speculate… there are tests that can help to determine if you have vacuum leaks, MAF, injector problem etc…

You say help diagnose so I need to ask… are you willing to actually diagnose this issue, as opposed to speculate?
Definitely want you all to help diagnose, also want to learn how to take care of this car a little bit more by myself rather than taking it to the shop on every single issue without a clue. I take this as a learning opportunity. Thank you for all of your prompt replies! Learning lots already 😀
 
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