Hello, I would be grateful for advice regarding some fault codes on my Octavia Mk1 1.8T AUM engine:

17705 pressure drop between turbo and throttle valve, check DV

17545 long term fuel trim add. Fuel Bank 1 system too rich

01274 air flow flap positioning motor (V71) faulty - intermittent

Also, what oil should I be using?

Finally how do I check my timing is correct? I recently had the cambelt changed. The car drives the same but I think the engine is a bit noiser. I asked the mechanic to check but he thought everything was ok.

Many thanks.

Assuming you haven't had a reply or read the forums.

The throttle's large electrically operated butterfly valve, is sticking at low revs. This controls the air intake.

Oil fumes from the engine are fed into the intake on the other side of this valve.

Because of a downward slope on the other side, the tars condense and cause a sticky gum to form at the bottom of the valve.

So it doesn't move smoothly It sticks and frees itself suddenly, giving these errors. Especially in cold weather, as it becomes like glue

You have to clean the bottom of this valve yearly.

You have to remove the large black intake pipe 3.5" in diameter (the biggest one). Undo the large jubilee clip and wedge the pipe out of the way

Place a large rag below the pipe to catch the carb cleaner as it runs out.

Push the valve open at the top, using a blunt end item, like your finger, gently . Be careful not to damage it.

Using a toothbrush with no loose bristles clean the bottom edge, after spraying with lots of carb cleaner.

Clean the back of the valve as well gently use lots of cleaner, £1 from What!

The carb cleaner will run back out onto the rag. Below it is the alternator I believe.Hence the rag to protect it.

Wait until the cleaner becomes clear.

Put the pipe back repeat every autumn.

Takes about 30 mins.

Wear gloves and don't breath the cleaner.

Don't use anything to clean, that can leave bits behind as it will go straight into the engine.

Use your covered finger to rub it clean.