MProved

Been having an issue with misfires on cylinders 2 & 4 but only when I go over 3500rpm or 1/2 throttle. Suspect it's the coil packs going bad along with spark plugs. CEL comes on and goes into limp mode with more than half throttle. Cant burn fuel so ECU shuts both cylinders and could down. Thoughts? I was quoted $350 to do plugs and coils in just those 2 cylinders. DIY?

fredtga

if the $350 includes brand new OEM parts, then it's not extremely bad; quote is for sure on the high side, but one Bosch coil is around $80 + shipping and OEM Bosch spark plugs are around $5 /each...

Ausmbtech

The coils very rarely fail and if they do they usually misfire all the time.

Misfire at upper rpm/load ranges is usually due to a lean misfire caused by the MAF sensor failing. Disconnect the electrical plug on the MAF and see if it still misfires. If not then replace the MAF and reset the fuel trims with a diagnostic tool or disconnect the battery for 5 mins.

MProved

Wouldn't there be a maf code? Occasionally my BAS and ESP light come on as well. Maf related?

eFifty5AMG

Mine did the same thing. Showed misfire codes, but nothing actually indicating it was a MAF issue. Replaced MAF & it hasn't been back; no codes & it's been about 5 months.

cm60k

Yeah, i replace "MAF & CPS" every 4/6 months,,

i'm wondering how those 2 little monsters affect directly to the Engine performance..!!

ZAYED,,

KJI3jflarryfe93

how do you afford buying new MAF/CPS every 6 months?
are these cheap parts where you live?
do you buy Bosch or genuine MB parts or maybe something else?

cm60k

Yeah sure, both are "Bosch",

*CPS:- around ($55)

*MAF:- around ($108)

ZAYED,,

MProved

Show me a new Bosch for $108

cm60k

How you want me to show you..[!?!],,

come here to the shop near me, and take whatever quantity you wish, ($108) for a piece, and ($102) if you take more than (5) pieces..!!!

ZAYED,,

MProved

I'm in NC can you mail one?

cm60k

Sure i can, shipping will be ($68), ($108+$68= $176)..!

you can get one locally cheaper, around ($150), from E-bay or Amazon:-

http://www.ebay.com/itm/Mercedes-Benz-Air-Mass-Flow-Sensor-MAF-OEM-Original-BOSCH-Germany-0280217810-/190772975906?hash=item2c6af49922&vxp=mtr
*

ZAYED,,

MProved

Installed brand new Bosch MAF. No change 😡

eFifty5AMG

And a battery reset?

MProved

Yes, there goes another $240

$4,000 come and get it. Drives great under 3500rpm

cm60k

Try to diagnose the car first..?, codes will save more time & $$$$..!

ZAYED,,

MProved

PO302 cylinder 2 misfire

Pulled plugs on cylinder 2 and they look fine. Swapped cylinder 1 coil pack with cylinder 2 and cyl 2 still misfired. Wires are my guess

cm60k

Yeah, it might be, it's better if you can replace all plugs with wires,,

did you check if Cyl #2 injector works well..?

ZAYED,,

MProved

How do I check injector?

cm60k

First put the key in position 2, then unplug the injector connector, and test the pins, if Electricity reaches to the injector, with NO cuts,,

after that star the car & see if Electricity still there continuously or not...!!

ZAYED,,

MProved

installed new injector, new MAF, new wires, new plugs, new coil pack. Still happening. I'm done

cm60k

Strange..!, did you still have P0302 code..??

ZAYED,,

MProved

Cylinder 1,2,7

I'm guessing it's electrical

cm60k

If all "MAF/coils/plugs/wires" are fine, then could be air leak somewhere that causes bad misfires..!,

did you check all breather hoses, or MAF breather hose or MAF upper/lower o-rings..!!

ZAYED,,

WVM

Hi. Similar problem here. Misfire cylinder 2. Coils good- i change between them problem still on cylinder 2, new OE plugs installed.
The car is pulling strong for 5-150 km, then the CEL light is back on.
Always the same error.
Give me ideeas please !
First time it happend is after i stage 1 the car !
Same tuner, other c43, no problems !