X15 chuffing through air cleaners at low rpm on jake brake

[Jakt2016]

I have an x15 that has been chuffing at lower rpms.. 1300 and below. On the 2nd and 3rd stage of the jakes. It is fine until it hits about 1300 or so. I just realized today that it's coming out of the air cleaners.I had a pretty bad manifold exhaust leak. So I replaced with a new manifold. But it's still doing it. This is an x15 that's deleted for about 150k now. I just recently replaced the turbo. But can't for the life of me remember if it was doing this before or after turbo install. Also just did an overhead too. Could this be a solenoid going bad?