Taking jerk & misfire in slow W211 E320 2004

[Asim002]

Dear Experts
My 2004 E320 has two issues
1- taking jurks (three or four) while getting slow (i.e when I release gas pedal and speed getting slow like bellow 20 KM/h)

2- Misfire or rough idle, for example I am stopped at a round about and while accelerating it refuse to get accelerate immediately sometime and I observe missing for hardly two to three seconds and than It goes.

I am planning to change spark plugs as they run around 90,000 Km already and guys can you please suggest which brand of spark plugs should I buy, Original Mercedes spark plug comes in NGK cost 37 each and Bosch cost me 15 each, which should I go for ? Is there any bad experience with Bosch ?

Thanks
Asim

 

[toolman1954]

Hi,
Welcome to the forum.
From the description of your problem, I would think that after 90,000 Km that a change of spark plugs is a good idea and may well alleviate your problem. When you remove the plugs, if you are to do it yourself, I would make a note of the colour of the spark plug tip, as this will aid any further diagnostic. Ideally you are looking to see a nice coffee colour, that would indicate good detonation. Anythig else and you may have other problems.
Now just as a thought, with the harsh weather conditions you have, it may be helpful to examine the spark plug leads for any signs of deterioration.
It can be useful to open your bonnet at night time, and see if there is any sparking across the leads at all, as this would show the insulation breaking down.
NGK or Bosch, I think that I would go the extra mile and put in the NGK, I know they cost more, but, again it is your choice.

Steve

 

[Asim002]

Hi,
Welcome to the forum.
From the description of your problem, I would think that after 90,000 Km that a change of spark plugs is a good idea and may well alleviate your problem. When you remove the plugs, if you are to do it yourself, I would make a note of the colour of the spark plug tip, as this will aid any further diagnostic. Ideally you are looking to see a nice coffee colour, that would indicate good detonation. Anythig else and you may have other problems.
Now just as a thought, with the harsh weather conditions you have, it may be helpful to examine the spark plug leads for any signs of deterioration.
It can be useful to open your bonnet at night time, and see if there is any sparking across the leads at all, as this would show the insulation breaking down.
NGK or Bosch, I think that I would go the extra mile and put in the NGK, I know they cost more, but, again it is your choice.

Steve

Thanks Steve
I had a thought about ignition cables and I checked their resistance (with multi meter) and it looks fine to me as average resistance that I observed was 2.5 K Ohm and acceptance criteria is 2 K Ohm (punched of steel part of cable. But yeah your idea sounds great I'll check tonight.
I am gonna take your advise and will put NGK from Mercedes Dealer.
I'll keep you posted

Thanks again
Asim

 

[Asim002]

Guys I am going to buy NGK and will share my experience with you all but can you please advise me on following

Which one is a better type when we talk about spark plug, For example I can see multiple options i.e Standard Plug, Iridium Plug, Iridium Laser Plug & Platinum Laser Plug on NGK website and it says all fit in my car.

I noticed people use iridium plugs mostly but isn't laser iridium and platinum sound better, Any advise from your knowledge and experience.

Thanks
Asim

 

[OneForTheRoad]

Provide the dealer with your vin and they will provide the correct plug. At £37 each I'd think they'd be platinum or iridium anyhow.

 

[toolman1954]

The plugs price will be in UAE Dirhams ( AED 4.81 to the £1 ) so it doesn't sound so bad when converted, about £7.70 each plug.
I have not bought spark plugs for cars for many many years, so would be perhaps just as confused with the choice of plugs available. Having scanned Ebay U.K. for NGK plugs, seems the most popular selling ones appear to be Iridium, so that would probably be my choice. Also defining the choice would be whatever is in there now, 90,000 km out of a set of plugs seems ok to me. So choose like for like.
I have a suspicion that they may well be more expensive at the Mercedes Dealer in Dubai, but there is no harm in checking.

Steve.