Wastegate or Turbo issue?

[BravoWhiskey]

I usually like a cruise setting of 30”/2300.  With a FF of about 18.  Motor runs smooth, temps where they should be and at 16-17k I am at about 178-184ktas.  I climb to this alt at 34/2400 full rich and between 500-700fpm unless ATC asks for better.  Where I run into my issue is once I level off and start pulling the MP back it will drop abruptly.  I start very slowly with this process.  But the drop is so significant you get a brief feeling you are losing power.  The drop may go from 32-23 in a second or two.  So I start increasing MP , again slowly.  It will hover at about 27-28 then jump back to 33-34.  This process of corrections takes a while.  And if a jump occurs when I am busy with another task my temps creep up on me. I use mouse milk on the waste gate but this seems to occur much more frequently than it should.  Does this sound like a Wastegate issue, or could this be an actual turbo issue?  I would think a turbo issue wouldn’t be sporadic like this.  

Anyone else experience this?  

[N201MKTurbo]

I have never worked on an M20M, so take what I say with a grain of salt.

These type of issues are almost always a waste gate or turbo controller problem. It could be the waste gate is sticking or something in the controller is sticking.

[Danb]

Wonder about the density controller.

[Fritz1]

my engine does a little of that of top of the climb reducing from 34" to 30", maybe bootstraps by 2" a couple of times, it is less pronounced when I reduce power slowly without touching the propeller, go down to 30", slowly reduce rpm and then reduce boost again, I have replaced my wastegate last summer at about 750h because it was leaking oil, boot strapping is about the same, I put a lavish amount of mousemilk on both sides of the wastegate shaft with a small brush at every oil 25h change. Take the return spring off your wastegate and feel how much it is dragging. If it is not dragging at all you may want to clean all hoses connected to the turbo controller, if that does not help you may want to have the turbo controller overhauled, a piece of debris may be stuck in there or a part may be worn.