I did a bunch of repairs on this Audi 5.2L v10. For a v10, this thing is not super powerful. But I actually really like this engine.
The vehicle came in for a check engine light and a inspection. It set a cylinder 9 misfire code and a knock sensor 3 signal low amplitude trouble code. I find a bunch of the ignition coils are only half way plugged in, especially cylinder 9. I remove coil 9 to inspect the spark plug. The plugs are OK, but many of the spark plug tubes are full of oil. The valve cover gaskets are leaking into the spark plug tubes. I plug in the coils all the way, and no more misfiring. In the very front of the engine, there is the electrical connectors for all 4 knock sensors. Two of the sensors have breaking wires at the connectors. I recommend replacing the valve cover gaskets, the two knock sensor connectors, and a few other non-related things. The customer also wants the intake valves walnut blasted. I get approval and start the job.
I'm about to remove a lot of fasteners and parts from this vehicle, I need to be organized and focused on what I'm doing. As I remove components, they get stacked on the shelf in chronological order with their fasteners. I remove the front bumper cover, bumper bar, headlights. I unbolt the radiator support and move it forward to gain access to the front of the engine. I start with removing all of the hoses then the wiring harness. I pay attention to how things are routed. I will mark connectors/hoses with paint pen and or take pictures if something looks like it could be mixed up. I remove everything from the intake manifold and valve covers. I now remove the intake manifold off of the engine.
I find a small plastic piece stuck in cylinder 7 intake port. I inspect inside the intake manifold and find the variable intake runner flaps are broken. I recommend replacing the intake manifold. I'm told the manifold is $7000, and the customer doesn't want to replace it. I open up the intake and fully remove the intake flaps and clean all of the sludge out of it. The intake flaps create a long narrow intake runner that accelerates the intake charge that helps with cylinder filling at lower engine speeds. At high engine speed/load the flaps open and create a short fatter runner. The intake will now have the short fat runner all the time. The engine will loose some low end torque. I leave the flap actuator on the manifold so it doesn't set trouble codes and silicone a plug into the empty hole where the flaps were.