Hey guys I'm new to the evo, just got my first one but I got a slight rough idle. It goes up and down sounds like as well a lil mis, I've notice all vacuum lunes are zip tie I have ni codes, and just put a fresh new plugs, any ideas anyone. Few mods like exhaust and intake and manual boost controller. Can someone please help.

 

boost leak test

 

Ok ill try test, thanks evodude

 

The Dude Abides.

 

I tested, everything good, double check vacuum lines and are good, I did unplug MAF and idle was perfect I connected it back and starts a rough idle again does that mean its bad, again I have no codes either.

 

Afr gauge??? Check your afrs at idle. Could be tune time.

 

Check the MAS (MAF) and clean if necessary..Good luck.

https://www.evolutionm.net/forums/ge...-cleaning.html

https://www.evolutionm.net/forums/ev...f-cleaner.html

 

IACV valve...
In my case it was the HKS BOV - needed a good clean inside as had a build up of dirt

 

Have a stock bov, and at idle my afr is like 15 to rich

 

And the tuning is stock

 

I had the same problem awhile back ended up being the egr valve. Replaced it and problem solved.

 

Would I get a code, if egr is bad? Just got back my evo and they replaced MAF but the rough still continues...

 

Are you sure you don't have Cams?

 

is your RPM jumping at idle? or is it just the exhaust note going up and down?

 

It idles and then starts to feel like a mis and then its fine but idle then wants to die out, and my afr goes up and down when it feels like missin it reads 17 and then it reads back to 10 idling fine but then back to miss and reading 17 again any ideas