Wire harness,O2 sensors,Leaky cam sensors replaced, result: worse gas mileage!!!
Two weeks ago I got the dreaded "Check engine light". Since my car is still under warranty (2003 C230 coupe w/ extended warranty) I did not worry about the cost.
So I took it to the stealership located in the beautiful South Bay, they found
leaky cam sensors, Bad O2 sensors,Engine wire harness, bad $12 dollar hose,after all said and done to my dismay, my car is been running worse(Miles/Gallons , city 16~20 Hwy 18~25) than before they replace all above mentioned items.
At the moment the car is back at the stearlership for this issue as well as for rough idle when cold. I got a phone message from the SA stating that they could not replicate or find any problems in regards to the poor gas mileage , but they will keep the car one more day to see if they can replicate the cold start rough idle.
Any input/ comments will be appreciated.
J.
Last edited by jimboom; Feb 10, 2009 at 11:08 PM. Reason: add words

Two weeks ago I got the dreaded "Check engine light". Since my car is still under warranty (2003 C230 coupe w/ extended warranty) I did not worry about the cost.
So I took it to the stealership located in the beautiful South Bay, they found
leaky cam sensors, Bad O2 sensors,Engine wire harness, bad $12 dollar hose,after all said and done to my dismay, my car is been running worse(Miles/Gallons , city 16~20 Hwy 18~25) than before they replace all above mentioned items.
At the moment the car is back at the stearlership for this issue as well as for rough idle when cold. I got a phone message from the SA stating that they could not replicate or find any problems in regards to the poor gas mileage , but they will keep the car one more day to see if they can replicate the cold start rough idle.
Any input/ comments will be appreciated.
J.
Sounds like a MAF that needs to be cleaned.
Are your tires properly inflated? How many miles on the car, last spark plug change? Are all the Coil Packs good?
What model and year is your car?
Spar plugs have less than 500 miles on them. I figure if is a dirty MAF or a bad coil pack the stealership should be able to diagnose this problems, but they keep saying"unable to replicate problem ."what should I do?

My only other thought would be that you could have a clogged air filter or catalytic convertor.
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And people ask
"is the extended warranty worth it?"
It is if you intend to keep the car.
You're about the 5th person to write lately of problems with
a 2003 M271 engine.
The Best of Mercedes & AMG

So the tale continues...............................
- Cam sensors
-Wire harness
-O2 sensors
-12 dollar vacuum hose
-Exhaust manifold gasket
-Piston head
-throttle body
-ECU
-Vacuum pump?
The car feels good now, no lag at acceleration. the only thing that worries me is some very faint knocking noise I heard the morning after I got car from the dealer. The only thing I can think of, is the valves needed some time to settle down?. I only heard the noise the first day I got the car back, but this morning is gone hopefully for good. I will continue monitoring the situation. If the noise comes back ,I will have to take it back to the dealer for a third time since this whole situation started 3 weeks ago. I hope I don't have to go back as this whole situation is becoming a huge pain in the neck.



