Since you just posted this, I am going to hope that you are perusing the archives and searching for some answers.

Vacuum leaks, are no different than on other cars....Look at all of the tubing, check for cracks, replace when in doubt.

Same with the fuel pump....it's electric...it's either hissing or it's not. Fuel filter is either filtering, or it's clogged. If you don't know when/if it was replaced, it's not going to hurt the car to replace it.

I think on your engine there is a idle control valve towards the front left of the engine. I have read that these can get groady and that cleaning them has done good things. Might wanna search for that gadget on this site first.

Good luck.

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It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D