I just installed them a few days ago and under 3k Rpms I get sort of a hissing sound from the intakes. Is this hissing from the intakes and is it normal or is it caused from a leak?

 

Mine don't hiss....you can hear a throatier sound of the air intake, even at idle. So I would surmise there may be a leak, I would check all of the hoses to ensure that they are on nice n snug.

 

Likely a leak. Mine don't hiss either.

Check the connections on the throttle bodies... after several thousand miles mine loosened up and needed to be readjusted (rubber was more pliable after several thousand miles of use, better fitment).

 

Sounds like a vacuum leak. If you can hear it in the car, should be easy to hear/find it under the hood.

 

Is it a hiss or a whistle?

Cone filters have a tendency to whistle.

 

My R2c doesn't hiss or whistle, it just roar above 5k and and stay normal under that. Hiss is definitely a leak.

 

I installed mine and now my service engine light came on.I disconnected battery to see if ecu would relearn it.3 days ago and now after a long drive.it's on again.any ideas? Car has 41k on odom.I didn't use the hoses it came with.used the stock hoses.they connected fine.should I use the r2c hoses and reset ecu again?

 

No reason these intakes should be throwing a code. I'd double check your installation, and get the code read. It could be something totally unrelated.

 

I changed hoses and tightened clamps more.also gave each sensor a little more turns tight. Reset computer so far no codes.that was a week ago