[n86121]

Perhaps a bit more expensive and invasive is to have the fuel pumps pulled and then setup on lab bench. Then checked on aircraft.

I had my entire rear fuel and intake system, throttle, intake, fuel pumps pulled and overhauled when I put in GAMIs. (TCM injectors were backlogged, but GAMI were available, so easy decision to swap them all).

I noticed after that the rear engine took almost zero manual adjustment with climb and descent. Pretty much deade center all the time.

Whereas the front I had to do a lot of leaning and fidgeting.

So next annual I had the same done to the front.
Similar results as rear.

They found ancient gaskets in throttle, and spider, leaky gaskets etc.

Ballpark total was around $1-2k each engine, but now the fuel systems are like new.