E20 fuel causing issues on my old C-Class? Noticing lag in acceleration

I only fill up XP95 and that too at a reliable outlet near my place.

BHPian Sanidhya mukund recently shared this with other enthusiasts.

W204 C-class sluggish when accelerating. Could E20 petrol be the cause?

Hello all,

I am creating this post to seek your views about a problem I’m facing with my 2014 W204 C200 CGI.

I bought this car a decade ago and have been maintaining it at the authorised MB dealership since. It has covered about 46K kilometres at the time of writing this. The transmission fluid has been changed timely and the oil and filter changes have also been adhered to.

Off late, I’m noticing the following symptoms:

When I’m on the highway doing 70-80 KM/h, and I accelerate from this speed to overtake another car, I notice a jerk/lag/sluggishness. The best way to describe it would be that whenever I suddenly accelerate, the car doesn’t pick up like it used to. It feels like it loses power for a few seconds.

There is no check engine light glowing. The OBD scan doesn’t return any findings.

A few suspects could be:

1. The spark plugs: Given the low running, the MB service advisor asked me to put it off for later because according to him, they can last much longer than 45K kilometres.
2. Fuel injector nozzles: The maintenance schedule specifies that they have to be serviced at a certain age and mileage. However, the MB guy told me not to bother, again, because of the low running.
3. Air filter hose pipe: there is a slight crack in the air filter intake pipe. I suspect it occurred when the front end was dismantled to change the radiator fan assembly at the dealership about a year ago. They told me not to worry about it and patched it with “cotton tape”
4. Lastly, could it be that its E20 petrol is slowly administering death to the car? I only fill up XP95 and that too at a reliable outlet near my place.

Would really appreciate your views on what could be the issue here.

Here's what BHPian Shreyans_Jain had to say on the matter:

While each individual point that you list can potentially be the cause, somewhere, the problem is interconnected.

XP95 is E14, which if the car is not rated for will corrode your pumps, injectors and spark plugs. The sad part is that there is nothing you can do about it. You’ll burn money to replace the parts, and then watch them fail again.

Here's what BHPian Jeroen had to say on the matter:

Couple of thoughts:

Yes, spark plugs should last longer, but he should have pulled them out to verify their condition at least!

That cracked inlet pipe. As long as the crack is before the mass air flow meter it normally isn’t a huge problem. But even so, the crack will allow warm air surrounding the engine to be drawn air, rather than cool air from the outside. But it will have to be a large crack before you would start noticing it in degrading engine performance.

I would check the air filter and the air intake. A dirty air filter or any obstruction in the air inlet circuit will lead to engine performance degradation quickly.

As no error codes are shown, another thing you might want to try is cleaning the air mass meter. Make sure to use proper air mass metering cleaning fluid. Not brake fluid or so.

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