So my cable is stretched as farrrrrk. Flatstick was only half open. Adjusted it as much as possible and now its 3quarter but still want that bit more. I've noticed the economy is a lot better now.
Where should I go to buy a new cable and is it easy to replace or should I get someone to do it for me.

An aftermarket cable will be cheaper than a genuine Ford part. Have you go a Super Cheap, Repco, Bursons or AutoBarn shop nearby?

It's relatively easy to replace the throttle cable. Start removing it at the throttle body first and note the way it's been installed. Then, with the cable slackened off, you can remove it at the top of the accelerator pedal. When in doubt of how something's assembled, take a few digital photos to refer to after.

Yes I have all of those near by. Bursons was always cheapest with my honda by a long way. Would assume the same with the falcon. How much approximatly would it cost for one?

You have to be careful what cable you get. 3.9L and 4.0L cables are different and weather it's a auto or manual as well. The 4.0L cable is a tad shorter then the 3.9 and will not fit at all.

But here are the genuine numbers & prices from ford all prices are + GST
EA9C799E 3.9L Auto $80.20
ED9C799B 4.0L Auto $72.59

EA9C799B 3.9L Manual Obsolete
EA9C799F 4.0L Manual $63.42

I would assume you have a 3.9L since 4.0L Autos didn't have any adjustment at all.

Hopes This Helps
Rick