rough idle after intake install

[Danbob]

Hey guys,

I put in my free ebay intake that I got from a friend who had an older 2.2 impreza. I didn't use a cone filter. I used the stock box with snorkus removed for more torque and cooler air. All of the hoses are connected up perfectly, and a reset the ecu by taking the negative terminal off the battery and waiting a while. I mean I have put in like 15 of these things on other cars so I could pretty much do it with my eyes closed on the side of a dirt road if i had to.

I started up the car, drove around, and felt my nice new powerful 2.2 liter beast LOL.

My only problem is that every time I came to a stop and the car was idling, it idled rough, almost like a chugging at some points, but never stalling. Kind of worries me. The only thing that I think it might be is that the Air Idle bypass line (you know the big thick peice of tubing that the ebay people forgot to put a hole for in their intake) well I rigged it up so that the big hose goes into a smaller hose, and that attaches to the intake so as not to have the big bulky hose attached to the intake...could this be creating the problem?

thanks - Dan

[Perdue]

IIRC, I had that larger hose run into a smaller hose and then hooked to one of the holes on my GPMoto and Cobb intakes. I then used tees for the other vacuum lines. Maybe something has clogged or you have a line that has pinched itself off?

[Danbob]

Well that's interesting...I have those hoses running into each other but I did not connect them to each other with any typed of seal...they are just plugged into each other.....maybe I should seal them better and my problem will go away. If anyone else wants to stick an opinion in, feel free. I must say I do feel a smoother power curve and more power when accelerating. I like it because the sound is just a bit louder and only at WOT, otherwise just sounds stockish but with more grunt...Thank god it doesn't have that Honda intake sound...

[Plays_with_Toys]

I would suspect its something with the idle air bypass. Since at idle is when that hose is actually important.

[Sarra]

On my 2.5 DOHC, I used a brass fitting for the idle bypass. The stock point where that bypass connects to the intake itself is actually a smaller ID than what I currently have on the car, and it idles at about 500 rpm, and very smoothly. Perhaps you should think along those lines?