The car is just not feeling right. The idle seems to be off and is riding very rough. Then when I accelerate with the pedal to the floor and then completely take my foot off the gas it make a big knocking sound. I have no clue why this would happen but the car just not seem to not be running smooth at all.

 

Well the good news is that most MB's are like lovers, wives, girlfriend/boyfriend and every once in awhile they don't preform as expected.

However it may be very helpfull if you could further define----"The car is just not feeling right"--Other than that give her a hug!!!

 

Major knocking and roughness can be internal to the engine, or external. You seem to have a 2004 E500, which MAY need engine mounts by now.

This video will give you some idea about diagnosis, and you can search this forum for how to change them, IF they are actually a problem.

http://www.youtube.com/watch?feature...&v=McdjABFZHAY

*** NOTE WELL THAT I DID NOT WRITE THAT YOUR ENGINE MOUNTS ARE DEFINITELY BAD. I WROTE THAT YOU COULD CHECK THEM. You were not able to supply much information, and did not mention any codes or check-engine light, so this check is just my suggestion. +++++

 

I second the motor mount issue. If it feels rough at either idle or under acceleration and makes a significant knocking sound, the mounts may be bad. Easy way to tell is 1) visually inspect them 2) feel for vibration at idle around the engine and if it's severe it shows you the mounts may be bad.

 

Thank for the suggestions. I am hoping that's what it might be on not a tranny issue. The car only has 53K miles on it.

 

Yeah it's possible they've gone bad in 53,000 miles - not as common but I know a few members that have changed theirs that frequently. It could be the transmission mount too.

 

I went out this evening and no knocking at all when I break. I don't know much about the mechanic issues but wouldn't I get the same knocking at hard breaking? Its literally only when I floor the acceleration and then completely remove my foot from the gas and instant pretty loud knocking noise. Almost like hitting a speed bump hard.

 

I hardly believe that braking will cause the motormount or transmission mount to react since the braking works on the wheels and not the engine. When You hit the accelerator pedal the engine produces torque and that wants to turn the engine on it's side, especially when You hit it abruptly or floor it as You mentioned.

I personally wouldn't drive it like that untill I knew what's wrong whith it, You could damage more things then just the mounts.

.........**Thanks**.

 

I agree... but let me know clarify. it only makes that noise not when I accelerate but only when I completely take my foot off after acceleration. Still could be motor mounts?

 

Yep, it still could be the mounts because when You release the throttle by lifting of the accelerator pedal the engine tilts back to it's normal position from a leaned position from which ever side the torque tilts it.

........**Thanks**.