0482

[Rawze]

popping back thru the intake can also be a severely clogged exhaust manifold, either due to turbo too high position at idle, or a different clog like cans not hollowed out properly after de-mandate, clogged exhaust or muffler, etc.

It can also be an intake butterfly valve slamming open/shut, or an EGR valve doing this.

If the engine is demandated, the intake butterfly valve should have had its butterfly removed, and crank case filter gutted or removed as well.