[Arnold1]

Hello everybody ! I just got this E55 AMG 2005 couple months ago it has 120k miles and been working on it since then , changed spark plugs & one ignition coil cuz it looked cracked. After that i send it to 2-3 shops they kept it for 3 weeks and they just got money from me for inspection and testing and nothing… so till now as i know they did told me one side of the engine ( 4 cylinders are missfiring) and as i know idle is rough and when u accelerating slow , missfire is noticable. When you step on it it has full power. They did clean fuel injectors , change spark plugs checked o2 sensors and its still missfiring. Any idea ? Thanks

 

[Starguy1]

Fuel pressure
Vacuum/boost leaks
Correct spark plugs
Ignition wires

These are where I’d start if this were my car

 

[Finny-E55]

If you have access to DAS... Run a real-time smooth engine running test. This will identify which cylinder(s) have the issue(s)...

 

[Starguy1]

Also, misfiring on one side only points to a damaged catalytic converter. You’ll need to get under the car and look at it, it may be dented and the damaged material inside has at least partially plugged that side

 

[Arnold1]

Also, misfiring on one side only points to a damaged catalytic converter. You’ll need to get under the car and look at it, it may be dented and the damaged material inside has at least partially plugged that side

Update:
So the shop that i’ve left the car they did fuel injectors
And some ignition coils and o2 sensors , i’ve already replaced the soark plugs.
Another thing ( the car has headers and im sure it has a tune on it cuz it doesn’t show the code for cats)
The car was working fine but it was still shaking after i got it from the shop. Shaking only iddle and lights on dash were flickering but driving was okay i had power.
Last night driving home i step on it and it was the CEL flickering and i had no power at all like choked i think it went to limp mode idk , turned it off and on and the car was having power but the missfire was still there. Sorry idk how to explain better

 

[Starguy1]

Do you have any documented fault codes and/or test results? It sounds like these shops are just replacing random things and hoping they got something right

 

[Arnold1]

Do you have any documented fault codes and/or test results? It sounds like these shops are just replacing random things and hoping they got something right

Yes i’m pissed off with them , po300 po301 po303 po305 po307
They changed them and they still comming back
I talked to the guy who used to have the car he said it used to have a euro tune on it and i think that fkd it up. Been checking today all day about it and people say that it can be the cause of it(ordering a tune imma tey it out this weekend) if nothing happens im thinking probably the ecu 🤷🏻‍♂️

 

[Starguy1]

It’s probably not the ecu, and maybe not a tune. But it may not hurt to return it to the factory tune. Those misfire codes aren’t on the same bank. If you don’t have access to diagnostic tools you should send this thing to someone who is familiar with Benzes, you’ll save $$ in the long run. If you want to try working on it yourself you’ll need an SDS computer to be able to perform the more in-depth factory tests and a fuel pressure gauge to start

 

[Arnold1]

It’s probably not the ecu, and maybe not a tune. But it may not hurt to return it to the factory tune. Those misfire codes aren’t on the same bank. If you don’t have access to diagnostic tools you should send this thing to someone who is familiar with Benzes, you’ll save $$ in the long run. If you want to try working on it yourself you’ll need an SDS computer to be able to perform the more in-depth factory tests and a fuel pressure gauge to start

So we tried to install a stage 1 tune , so at least we know what we running. After it installed car didn’t start at all (made some click click ) sounds as soon as u turn the ignition on but doesn’t start & even doesn’t read the ecu anymore i think imma have to buy an ecu now…

 

[Starguy1]

A clicking noise almost always means the battery is dying. Connect a battery charger and try again.

 

[Arnold1]

A clicking noise almost always means the battery is dying. Connect a battery charger and try again.

It was bad file we brought it back to stock
It missfires on the idle and when u stop at stoplight you can hear the engine almost stalling and shaking.
After a little stop staying it flashes the CEL goes to limp mode. Codes i read after this po300 po303 po305 po307 again

 

[Starguy1]

If you want to tackle this problem yourself, and do it properly, you need to get some diagnostic tools. At least a fuel pressure gauge and some sort of scan tool(the more expensive the better, it will have features that will make this process much easier). If not, take it to someone who really knows at least German cars. But a Benz-centric shop would be much easier in the long run

If you really want to just continue throwing parts at it you can replace the plug wires and at least pull some plugs and make sure they are the correct ones

 

[tony1963tony]

No modern scan tool = no tools.