Hey everyone had this issue for the last 2-3 months with no progress but a lot of time and money spent so wanted to get some insight from you guys.

I have a 2005 Mercedes Benz C180 which has done about 85ks.

First noticed the problem and a pattern where it would always occur, 5am Mon-Fri when the car is cold. Jumping on the highway once i hit 80km/h after a couple of seconds Cylinder 2 would misfire and i would get the usual loss in power and very rough drive when Gas is applied. Also extremely rough when idle. Resets and problem gone if i turn the car off.

Although on the way home after my shift (1pm) when jumping back on the highway this problem wouldn't occur, it would only if i push the gas to try take over a car going over 100km/h.

(First Mechanic Visit)
I was also due for a service so his recommendation was that i was due to change my spark plugs which may be the issue as well as my service. Got that those 2 issues done and $ spent. Noticeable improvement in my drive for about 3 days then the same problem came back.

(Second Mechanic Visit)
This time he decided we the next culprit was the ignition coils and we swapped over coil 2 & 4 to see if cylinder 4 misfires. Again seemed alright for 1-2 days then the problem returned

(Third Visit)
Now he wanted to do a proper diagnostic to try and figure this issue out so i left the car with him for 1 week. He then gave me a call to say that he would need to 'remove air filter housing, intake pipe, manifold and supercharger to gain access to breather hoses and valve' suspecting an issue there. He identified a split in the hose and replaced it. This came to a hefty bill but said the problem should most likely be sorted. Same issue returned a couple days later.

(Fourth Visit)
Visited him just before Christmas at this point. He put in some Fuel Injector Cleaner and said our next process was that there may be a contamination in the mass airflow valve. Now that the break is over the problem is consistent and getting more prominent.

Booking in to get my car Warranted and go through with the next step but wanted another opinion in case anyone has has a similar issue as the costs are getting out of hand.

MUCH appreciated if anyone could give me their input or advice on this matter as im not really a car-savy person.

Thanks Guys!!

 

I had that issue turned out to be the wiring harness to the spark plugs.. Have you looked at that. They tend to get brittle and snap..

 

Dear Sir,
Have you tried plugging in an obd2 reader and getting the code? If not, that's probably your first step. You can buy a reader at Walmart of Advance Auto. The code should tell you exactly what's wrong. Your mechanic may or may not have been honest with you, although plugs and coil are usual suspects.

Plus these are items you can do yourself for almost nothing. This forum has tutorials that I have found quite useful. Also feel free to PM if you need help!

Sorry you have to go through this crap it's so frustrating

 

Thanks for the response guys! Much appreciated.

The code that has been consistent through this time is,
P0302: Misfiring of Cylinder 2.

Again to summarize what has been done so far:
- Full Service
- Changed 4 sparks, 1 & 2 plugs were water damaged.
- As stated by mechanic [Remove air filter housing, intake pipe, manifold and superchager to gain access to breather hoses and valve] Which had a leak and was replaced.
- On second cycle of fuel injector cleaner.

Again was minor improvements where the problem would go away for 1-3 days then would return. Since then problem is a lot worse and occurring much more often.

Not too car-savy but definitely can give things a go with the aid of tutorials. What would you guys recommend i should take for the next step? wiring harness to spark plugs?

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Again thanks a lot for the responses and potential saving me more $$ that i cant currently afford!

 

Have you revisited the spark plugs? I'm curious to know if #1 and 2 plugs are still wet with water. Were they actually wet or had white deposits on them? Is this on the outside of the plug or the part inside the cylinder?