S70Houston

My 2003 E320 seems to be idling a big rough lately at cold start in the morning, which improves once the vehicle warms up a bit. (And I am in Northern CA, so it is NOT cold in the mornings, ..... possibly a bit "cooler").


Furthermore I notice a bit of a "sluggish" performance after depressing the accelerator pedal, almost feels like there is some kind of a delay before the car reacts?????


Service C is due in approx. 3K miles, vehicle currently has 83.3K miles on the clock.


Any ideas?


Thanks in advance.

kajtek1

Beside hooking up SD, you can run fuel cleaner, like Chevron brand, or Seafoam.

F1Fan

Does the idle quality seem louder also? Do you feel more vibrations in the car? If so, you might have torn engine mounts, which is a very common problem in the W211.

Symptoms include rougher idle, louder engine noise, sluggish feel, more engine vibration in the car.

S70Houston

Thank you very much.

The symptoms are mostly obvious when the car is cold, not when warmed up.
Yes, it does idle a bit rougher and is somewhat sluggish. But why would a bad engine mount cause a sluggish performance?

kajtek1

How do you know it has sluggish performance?
Did you measure difference in 0-60 time?
Placebo effect is always very strong in such cases, so without stop watch we are in dark.

S70Houston

What is a "Placebo" effect?

The vehicle just seems to idle a bit rougher and once depressing the accelerator pedal, it seems the car does not immidiately respond and there is like a soft growling noise (not sure how to poperly describe it) before the vehicle responds. There just seems to be a very slight delay before I can feel that the car does apply it's power.

No, I did not measure with a stop watch, but I think I know the car well enough to be able to notice the difference.

I will check the engine mounts this weekend with the procedure of someone pressing the brake and gas pedal at the same time while the car is in DRIVE or REVERSE to see if the engine moves.

kajtek1

Placebo effect is when the owners feel the car gaining more HP after changing the oil, or putting new air filter on it, or low-profile wheels.
I joke that my car always run faster after vacuuming the interior.
Human are very prone to it and it would not surprise me that car shaking at idle because of bad MM was taken for performing bad at highway speeds.
So get stop watch and give us number we can talk about.
The load test with brakes on does not work well on fluid-filled MM.
All the engines I tested move more with new MM than they did with worn out.

cmriv

whens the last time your rpms have gone above 3500? Alot of people baby mercedes like they are infants. Can't imagine what the carbon build up on a 14yo vehicle with 83k miles is. Is your transmission fluid level correct? This could cause a lag as well when fluid is cold, as it heats up it expands making it the "correct level".... if you get what i'm saying... run codes and see if anything comes up...

beejAMG

all of the above...

but ill do tcu reset first. its free, takes less than 3mins and does wonders. search about it.

S70Houston

Both Motor Mounts AND Transmission Mount were shot!
Replaced all and did a Transmission Service which was due anyhow, last one took place at 39K.

Car rides and drives like a dream now and NO, I do NOT baby my Mercedes, but it does not get abused either, it goes above 3500 RPM regularly.

cmriv

Glad to hear you resolved your issue.