You never know, i've had knocking in my car at a certain RPM and then it goes away.

 

long shot but do you have both clips in your snorkel to the air box. My friend had one of the clips missing and everytime it hit 5k the thing would somewhat die out. Good luck hope you figure it out.

 

i would change the spark plugs for one step colder, new coils, and get a tune for the intake and exhaust. should fix the problem

 

Is you BOV venting to atmosphere? You should try putting back in the original BOV and put back the original intake. It may be the parts you are installing. Evos do not like aftermarket intakes without a proper ECU tune and the Evo uses MAF sensor - a BOV can cause a lot of problems if it isn't recirculated.

 

If its in 3rd,4th or 5th and he has no boost controller w/ that cutout he can hit boost cut easily ...

 

dude i had the same problem. i put the k&n typhoon intake on a brand new evo with no other mods. in 4th and 5th gear at 5000 rpms the entire car would shake pretty bad. i read an article that the ecu would notice an increase in air flow (making the mixture lean) and would suddenly decrease boost to about 12 psi. i called k&n and they would not admit a problem with the intake. frickin liars. i put the stock intake pipe back on with the k&n adaptor and filter. i custom made some brackets and bolted them on to the intake adaptor to keep the intake from moving. the car runs strong and sounds good. not sure what k&n did to the intake, but other manufactures are not having these types of problems. i wanted to get other people with this same problem so we could all contact k&n and try to get a refund or another solution. know i am stuck with a cool looking intake pipe that remains in its original box. good luck.

 

yeah it sounds like its running lean when you hit 5k rpm. Check plugs and if they are gapped beyond stock...SET THEM BACK and GET A TUNE!!