Sputtering/misfire problems
 

My CEL keeps turning on because of a misire in cyl 4. Not sure if its a bad injector or boost leak. Usually after 3,000 rpms it misses but its not an all the time ordeal. I replaced all spark plugs with some ngk coppers and also replaced the coil. Haven't ohmed the injector out yet. Anyone know the specs?

The only thing done to my s4 is an HKS filter. Besides that it is completely stock and i am getting horrible gas mileage. Don't know too much about s4's yet being that i am a Z guy. But any help is appreciated. Thanks

did you replace all the coil packs? also did you gap your spark plugs? (.23) did you replace your entire air box with an HKS cone filter?

swap the injector with another one and see if the misfire moves

Should i run some injector cleaner. Think that might fix it?

I didn't replace all coil packs its just misfiring in cylinder 4. The whole airbox is gone there is just the hks filter. Also i just put brand new ngk spark plugs in a couple weeks ago that didn't fix the problem

Hey guys. I replaced the injector, coil and spark plugs and it is still throwing a code. Could it possibly be a vacuum leak or possibly a new fuel filter?

Did you keep/move your icm to a good place or did you just remove it?

Whats icm mean

Ignition control module. It sits on the heat sync on the factory airbox

Well i put the factory airbox back in so its bolted to the top of it

But it's probably bad. Find someone close with an s4 and test it with theirs