CLK 500 uneven

[x332race]

My CLK 500 has just been serviced......all normal items undertaken plus all spark plugs were replaced.

The car seems to run perfectly for about 20mins and then will be a brief period of "unevenness" from the engine, usually at a road junction at idle, and then it will be ok again.

Any ideas?

 

[Bobby Dazzler]

Air injection pump or relay?

 

[AndyPCD]

Could be one of the coils on its way out where it has been disturbed by the plugs being changed.

 

[BaldGuy]

I bet its plug leads.... Mine did exactly the same after my plugs were changed... never did change the leads as I lived with it as it was minimal.... A set of leads are anything from 100 upwards....

 

[x332race]

Would these matters be spotted on a diagnostic computer?

Would like to get it sorted as my wife is complaining about it!!

 

[IanW]

I had exactly the same problem on my CLK500, again immediately after it had been serviced.
A quick inspection showed that the plastic engine cover had not been engaged correctly with the air intake pipe at the rear of the engine.
Removed the cover, lined it up properly when replacing it & all hunky-dory.
HTH,
Ian.

 

[x332race]

I had exactly the same problem on my CLK500, again immediately after it had been serviced.
A quick inspection showed that the plastic engine cover had not been engaged correctly with the air intake pipe at the rear of the engine.
Removed the cover, lined it up properly when replacing it & all hunky-dory.
HTH,
Ian.

Thats easy to check so will do so before I do anything else! Will let you know how I get on.

 

[johnpidge]

Have this on my CLK55(208) plugs were changed 6 months before I purchased it (the service history confirms this) changed the MAF sensor - a little better - suggested it may still be plugs or leads even though its clear when checked on star diagnostics - kindof live with it and it doesn't seem to get worse - just a bit of a pain - runs fine then when warm runs uneven. Odd not everytime and sometimes worse (usually when hot) than other times. Leads sound expensive??

 

[x332race]

I had exactly the same problem on my CLK500, again immediately after it had been serviced.
A quick inspection showed that the plastic engine cover had not been engaged correctly with the air intake pipe at the rear of the engine.
Removed the cover, lined it up properly when replacing it & all hunky-dory.
HTH,
Ian.

Checked engine cover today.....all seemed to be ok at the rear of the engine but found that one or the plastic ducts leading from the air intake over the radiator was disconnected.....would this make a difference.....I'm thinking that this would draw warmer air into the engine when car stopped.....as we only get the problem when the engine is hot, is this likely to be the problem?

 

[BlackC55]

I doubt it. You really need to get it on a Star and check the smooth engine running data. The you can pinpoint the miss.

As baldGuy says it is most likely to be a plug lead problem or coil.

 

[alexander patie]

plug leads are usually fairly easy to pinpoint with star, there is a shut down facility to run the engine on just one set (ie a or b) of coils/leads. incorporated into this facility is the misfiring data for each cylinder, easily done with a little intelligence and care.

 

[x332race]

Have now driven the car....did not have a re-occurrence of the problem....maybe it was the loose inlet pipe to the air filter??

 

[x332race]

Have now driven the car....did not have a re-occurrence of the problem....maybe it was the loose inlet pipe to the air filter??

No more problems having now driven the car for a couple of days......Thanks IanW for suggesting I look at the air intake pipework / box....