Haji3978

Hi Guys,

New to the Forum, haven't posted anything up until now.

My car has a rough idle but drives fine even when I push it hard, it has a stage 2 - Down pipes, tune and BMC filters.

I took it to a performance shop and the guy thought it may be the tune so he flashed it stock but the rough idle is still there with factory tune.

Any ideas? Spark plugs? Coil packs? no CEL except the P0420 & P0430 becasuse no CATS.

Thanks

C3504matic

Could be plugs as tunes will eat them up .....I'd change those first

Haji3978

Thanks bud, booked into Mercedes for a change

tekfoc

Have coil packs checked also
There was a bad batch in the pass
They were all replaced on my car

Stevestil

which tune are you running

Haji3978

Thanks @C3504matic turned out to be one spark plug that was causing the issue - Mercedes replaced it under warranty - idles smooth again!

@Stevestil - Car was tuned by theses guys https://dyneperformance.com.au/ - im looking at getting it re-tuned though - Id lobe to get a DME tune but they are so expensive.

Thinking of going to see Gordi at https://etunersmotorsport.com.au/ - Heard he does some magic for the C63s

BMS

Easy fix!

Plan B could be to throw a JB4 on top of your existing flash map if you just want to dial it up (or down) a little.

Haji3978

Not really a fan on piggy back stuff @BMS - I've texted Gordie just waiting on a reply on when I can take it in. In the interim I hope the cat less P0420 & P0430 CEL codes don't cause issue to my engine ...

I've been reading about the different tunes available and the different power outputs - wonder how some tunes are making extra power without getting heat soak hmmm.....

Looks like the DME tune is the most aggressive and most power making tune from what I read