008465 Throttle Valve stuck open - advice please.

[Kojak]

For a while now I've been having VCDS errors to do with my EGR but after spraying some Diesel Applicator into the air intake, the fault clears for a few weeks.

Anyway, now I have 008465 error. What I'm wanting to know is, is there anything an average Joe like myself can do to clear this? Every time I clear it in VCDS it returns again going through the gears. I have searched the forum and found 2 other instances of this. The first was some mangled teeth on a sprocket wheel (or similar) and the other was a dirty plug/connector on the sensor (?).

Now I am not an expert at all regarding engines so I don't even know where the EGR or this throttle valve are located with the engine bay.

Should I just leave it in to the garage and pay the big bucks or is there anything at all I can try?

One final thing... regarding the EGR, someone on here mentioned Terraclean before. I know nothing about this but could it help any of these issues?

Thanks guys.