Attempting to speed up from stop to 45 mph and rpms rose above 5000 to 6000 and car would not speed up past 35 mph. I tried flooring the accelerator but nothing happened. No response at all past 35 mph. I pulled over and turned off the car for 5 minutes. Then I started the car again and the acceleration performed as it should.

- Laguna Niguel, CA, USA

Zero issues with this car until now. This week, June 2013, the car has 78,000 miles on it. I pulled up to a stoplight off the freeway, and the car started sputtering like never before. The check engine light came on - for the first time ever. The car stalled and engine died. It restarted, but when I pressed the gas there was no power, traffic was coming up the off ramp fast, I had to flash my brakes to get them to notice something was wrong but it was a close call. The car sputtered into the middle of a busy freeway overpass intersection with my family on board and eager traffic behind me. It was a very scary moment because the car went from completely reliable and trustworthy to complete loss of power and instability. I sputtered back home, creating the same dangerous conditions at every intersection. I took the car to a Mercedes Benz shop the next morning. After a lot of testing it was determined that the intake manifold needed to be pulled to look deeper into the engine. Hours later they found that the problem was caused by a defective plastic bushing of the intake manifold which broke and was sucked into cylinder #4 and #3. this caused the valves to bend and compromised the integrity of the cylinders and valves, according to the Mercedes qualified technician. There is extensive damage to the valves, and they don't know what all they're going to find once they pull the headers off. The cost to repair the car is $4,400, but it may even be higher. The cylinders have to be sent to a machine shop to see if they have any other issues as a result. Who knows what they'll find. The mechanics stated that Mercedes Benz is aware of this problem, that those moving plastic parts in the intake manifold are known to crack and cause problems and should never have been made out of plastic, but I don't see recalls on this obvious engineering & manufacturing defect.

- Scottsdale, AZ, USA

My check engine light came on so I went to mechanic to check. They performed a computer code test to find problem. The code indicates that the balance shaft is starting to fail. I researched on-line and discovered this is a known defect within this engine. Apparently Mercedes is unwilling to assume responsibility for this defect. Repairing this problem is extremely costly and the buyer shouldn't bare responsibility for their faulty parts. I understand there is a class action lawsuit filed, but I can't find out the current status of it. This defect can cause immediate engine failure when driving causing the auto to stop in traffic. Being that thousands of Mercedes vehicles have this defect I don't understand why the ntsb isn't stepping in.

- La Crescenta, CA, USA

I was driving home and noticed that when I would accelerate after coming to a stop the car was extremely slugglish. I would have to almost floor the gas pedal in order for the car to begin moving. I pulled over and then put the car in neuttral. The jerked violently and shifted very hard as I then tried to put it in reverse and the into park. I tried to put the car back into drive and it would not accelerate at all. I had to turn the car off and then back on again in order to get it moving. The gears continued to shift violently. However, when I finally got moving again, the car would not go over 35 mph. The car was inspected and an error code for the internal speed sensor came up, which is part of the valve body for the transmission. My car only has 59,000 miles on it. Mercedes is very aware of this problem on 2006-2007 C230 models! in fact, they are having a dispute with the manufacturer of the valve body because it is poor quality and defective. I have seen numerous other complaints related to this issue. My local Mercedes dealership quoted me $2,400 to repair this defective part. I was lucky in that I was not driving at 60 mph on the highway when this malfunction occurred. This is an extremely dangerous issue and a recall should be issued for this part.

- Miami, FL, USA

Took our daughter's 2006, C230 Mercedes Benz to our Mercedes certified mechanic to repair a sluggish problem that caused the check engine light to come on.. I was informed that a part in the engine called the balancer was going bad... the cost is an approx $5000. And that we would have to take it to the local Mercedes dealership to do the repair. The part installed in the 2006 and 2007 models was made of a too soft a metal, so its a defective part to start with! this part apparently causes the engine to lose power while driving... Benz has not issued a recall on this part.

- Tucson, AZ, USA

Took the vehicle to the dealer when the check engine light came on. Car was diagnosed with a bad balance shaft that needed to be replaced. Apparently this has been a problem with this engine on numerous models of Mercedes as class action lawsuits have been filed in numerous states.

- Silver Spring, MD, USA