hi, i have a 99' slk 230k with 38t miles on the clock.... it misfired the other day, no check engine lights have came on but car was running funny. it began to struggle to pick up speed when you accelerate but drives fine when below 3000rpm...i had it into a german car center and it came back with around 6 faults from the diagnostics machine inc something about catalytic problem, wrong fuel mix, valve 1 + 2 problem and a misfire..... just what i wanted to hear!!!!! all faults cleared and was told to give it a couple of days and see what happens!! it is still the samei.e spluttery when you accellerate and a bit jumpy......does anyone have any idea or have this happen to them?? thanks gnic

 

What are the OBD code numbers which were showing when connected to the diagnostics scanner? e.g. P0173

Are you sure your Check Engine Light CEL is working? i.e. comes on at startup. Surprising that there is a misfire and the CEL is not illuminated!

Stuart.

 

I would bet that it is the Mass Air Flow Sensor, I just replaced the one on My 01 slk320 it was doing the same thing over 3000 rpm but the check engine light was not on,I was able to pull codes out of the computer andthey were misfire cylinders 1,2,&3 plus fuel trim malfunction. After I swapped it out the car was running great again with no hesitation.

 

hi, thanks for response guys!!!
it sounds almost identical to the maf sensor post, i am going back tommorrow to the garage so will let you know!!

 

When MAF gets deirty of heater wire gets contaminated it makes angine give all sorts of codes. Best best is to liberally sparay clean, reset codes and go for a drive.

Bazzle

 

hey, thanks for your advice....m.a.f sensor replaced and fault has cleared!!!!
pity it cost £300!!!!!!

 

...particularly when the OE manufacturing price from Bosch will be circa £1, if not less.

MB parts "pipeline" must have overheads akin to their Showrooms

Stuart

 

YES 95% AIR MASS SENSOR REPLCE PROBLEM SLOVED LET ME NO HOW YOU GET ON.....NAZ B