Sksamg1993

Hey guys so the past 2 weeks my car has been misfiring and I've taken it to the dealership, they switched out the intake manifold gaskets and seals as well as spark plugs. Few hours after i took it, it started to misfire again so i took it my mechanic, he switched out the ignition coils for cylinders 4 and 2 that were misfiring. Took the car and after 2 days the check engine light came back on and started to blink this time. The codes read (sorry using photographic memory now), right engine bank emissions to high, air to fuel ratio to high, highly riched fuel. My tuner told me that those codes are something else and that my tune is still on the car. But now i am hearing an engine knocking sound and the car is shaking violently. Few friends told me it might be the lifters. Anybody got any idea whats going on, I've had the car for 2 years stock and 2 years with its upgrades and this never happened.

2011 C63
Kleeman stage 2 long tube headers

CarHopper

Were the MAFs looked at?

Sksamg1993

what are those?

cmacclel

Mass Air Flow Sensors.........You have 2 in the air boxes.

CarHopper

And if they are dirty or have a lot of miles on them could cause issues with airflow which can lead to your misfires.

Just spitballing here, but if they haven't been looked at and you still have issues could be worth checking out.

abcut973

Ok what code did you have?
Misfires can be a lot of different things. Dealership take your car in for a misfire and change the intake manifold gasket?? You must have had a vacuum leak too. Either way that is half a job from the dealership. What I don;t understand is why didn't you bring it back to MB?
They initiated the repair and should have been notified that the problem is back. They would have investigated further.

Sksamg1993

After they told me that i needed to pay 600 dollars for new 02 sensors without labor, i just got mad and left. i told them i don't have 02 sensors anymore cause my car is tuned and has no cats, they could have worked on it for weeks and just kept charging me and they told me the first day my LTH and tune has nothing to do with the problem. Then they came back and said it is the problem, they obviously just want to replace everything at my expense. So i didnt want to keep dumping money into it. I just sent it to Colorado Springs to my tuner and hopefully it might be a tiny fix. i just turned it on and the engine knocking sounds was so loud but not miss firing. Hopefully il know by tonight or in a few days what the problem is and il post the results.

cmacclel

I have worked on cars for 30+ years and never heard of a engine knocking loudly be a tiny fix.

Sksamg1993

Well was just hoping something needs to be replaced that's not to expensive or the tune needs to be reword or re-flashed only time would tell.

CarHopper

Just because you have LTH's doesn't mean the o2 sensors are no longer there... They still are in the pipes, just tuned out. The dealer also probably said you needed o2 sensors because they would be registering as bad or just would kick back an error when the mercedes dealer plugged your car in. Also, o2 sensors on these cars are expensive, sure you could probably find them cheaper but that number doesn't surprise me.

Next, you still haven't mentioned whether or not any mechanic has pulled and looked at your MAFs. How many miles on your car? A 2011, maybe 50ish? If the MAFs have been in place the whole time it wouldn't surprise me if they needed to be pulled and cleaned.

It sounds like the dealer took a stab at a possible vacuum leak and the fuel/ignition system. Only thing left is air.

Sksamg1993

my car has almost 59,000 miles on it and yeah i never changed the air filters. Im waiting on my mechanic to tell me whats going on exactly. but if the MAF's were bad would that cause a blinking CEL and the car shaking.

CarHopper

Oh yea, think about it. Takes two things to make the car move, fuel and air. Both have to be regulated within certain parameters. Now, you throw in some bad MAFs sending funky readings to the car about airflow and the car makes adjustments on those bad readings and you'll have misfires and shaking galore. Depending on how bad those misfires on the CEL may blink.

This happened to me once. I started my car and was shaking, misfiring, blinking CEL. Turned out to be a fluky type thing but the codes were just for misfires at the time. The car just couldn't catch up to itself. Not related to your issue, but just going to show how sensitive the car can be at times.

Like I said, it seems like they've covered most of the bases on fuel/ignition so I'd look into a possible air issue from here.

Sksamg1993

yeah i told my tuner to take a look at it, if that seems to be the issue, then it will much cheaper in repairs. im assuming thats a cheap fix.

CarHopper

MAFs are about $240 a piece and o2 sensors are also about $240 a piece. This is from an online source, not a dealer.

Gerry_M

You still have functioning O2 sensors. You should have two per bank, one pre catatlytic and one post catalytic for a total of four. The Pre-cats should be working, if these are off you have some problems as the cats has no AFR feedback for fueling. The Post -cats can be turned off as it only checks for cats health and if you dont have one in your LTH, these should be off. The dealer might think you need new O2 because the post cats are off or maybe they are smater than that and actually see the pre-cats O2 having issues.

bhamg

RockAuto

BOSCH Part # 17016 OE Style Oxygen Sensor; Wideband A/F; Wires: 5; Length (in): 20.9 One of our most popular parts
Upstream; Bosch is the OE equivalent supplier (Only 3 Remaining)

$94.79

I am Jeff

I can vouch that the bosch 17016 are the same as oe Upstream o2 sensors. I paid $104 for mine at the time.