amgstyle

hey guys my slk 32 is misfiring everytime i give it wot. it happens when the rpms climb up to redline, rite when it shifts to the next gear. i went and got the codes read. this is wat i got.

p0305 - cyl 5 misfire
p0303 - cyl 3 misfire
p0306 - cyl 6 misfire
p0300 - random/multiple cyl misfire

with all these cylinders misfiring could it be the coil pack, spark plugs, or wires. or is it something serious were it's gonna cost me a fortune? any info will help. thanks guys.

NitrogenBalance

I think someone here just had their cats replaced and if I remember was having the same issue at WOT....

ArsnlKen

AMG,I was reading about misfires on a thread in the C Class W203 forum just yesterday & alot of people had the same prob;in fact one guy had the same error codes as yours. Most of those w/probs wind up w/it being a vaccum leak & usually the hose that fixed the prob was about $12. Others had the misfires taken care of by changing sparkplugs & wires. Granted,these were all C Class W203's (230K's & 240's),so not sure if finding the thread will help or not. Hope so! Good luck!

///AMG4EVER

amgstyle - Is your car stock?

Eleventeen

Same crap I had going on. Most likely your cats.

https://mbworld.org/forums/c32-amg-c55-amg-w203/249273-high-rpm-misfire-solved.html

amgstyle

thanks for the help guys.

my car has the evo stage 2 kit, with code3 intake.
how can i check to see if it's the cats? it would have to be the primary ones cause i gutted out my secondary cats.

M_M

I had the same problem before, turned out it was due to cracked header. I'd suggest you go find a muffler shop to check whether there's any vacuum or exhaust leaks first.

sales@eurocharged.com

Yup, same exact problem as me. I checked EVERYTHING else, but it ended up being the cats. As soon as I hit redline, the car would misfire. Up to that point, the car was a beast.

Go get the cats checked!!

///AMG4EVER

I recommend you check for the obvious first. I was having a similar problem which got fixed just 5 days ago. LET had my car for a complete day and they checked everything; from the intake, to the cats, to the sensors, to any IC leaks, any loose spark plugs/cables... everything obvious that might've caused a malfunction at high boost.

I don't know what Erick did, but once the car was putted back together, the power was back to normal with no more CEL's. My conclusion: a leak!

I've read the evo headers were having some cracking issues. I would start there.

ohlord

have one misfire on the bank one and two on bank two,doubt that you cracked exhaust manifolds on both sides.Don't change plugs or wires or coils.3 going out at the same time would also be in doubt.Cat would throw a code either cat or o2 sensor codes.
When did you last change your fuel filter?How many miles on the car?
http://www.autohausaz.com/search/pro...@Fuel%20Filter
You need to check items that affect both banks.Fuel filter first,then vacuum leak since you don't show a code typical of a leak,start with the fuel.
ohlord

sales@eurocharged.com

The only code my car had was the misfire code.

amgstyle

when you say senors, wat senors should i be checking??

also i don't have the evo headers just stock headers.