I have a friend with a bone stock Evo9 MR. Today he added a Jmfab intake with a Perrin filter. Now when he slows down at a stop light it wants to stumble. He let the car just set and idle and after a few seconds it will drop down to 500rpms and start stumbling. Any ideas guys?

 

Maf plugged back in?

With the new intake is his bypass valve venting to the atmosphere?

 

MAF is plugged up. The boost cel is plugged into the intake pipe also. I just took the pipe off of my car to go SD. Its hooked up just like I had it. Could it be he is getting that much more air that it has thrown the tune off? We tried resetting the ecu by un hooking the battery.

 

My vote is to get a tune.

 

Bpv on backwards?

Remember the top hat to say goes towards the front of the car.

 

Boost leak test done?

 

Post a pic.

 

I'll see if I can get a pic.
Bpv on backwards? What is the BPV?

 

The bypass valve...or some ppl refer to blow off valve

 

Here are the pics. Hope it helps. He doesn't have anything on the crank case vent on the valve cover. Not sure if that's it.
http://s1338.beta.photobucket.com/us...tml?sort=3&o=0

http://s1338.beta.photobucket.com/us...tml?sort=3&o=1

http://s1338.beta.photobucket.com/us...tml?sort=3&o=2

 

Probably needs a tune. Common issue when changing out intake piping.

 

MAF probably isn't playing nicely with the new intake. Tune it.

 

Put the stock intake back on the car until you guys can get it tuned, also would be a good idea to check for leaks in the intake post MAF that could be causing the idle die issue.

 

Check the piping couplers behind the MAF. Something might be leaking air. Funniest thing is a boost leak wouldn't be able to determine that because you have to remove intake to check for leaks, LOL

 

Take another photo of the bpv, looks to me its not installed correctly