Misfire. The sequel

[Boo]

After my last plea for help, misfire, I went along to my local techno buddy for some help with this problem. Unfortunately, as with every one else I have encountered on the subject of tune ups and fault diagnosis, there was a sucking of air through the teeth when asked about the subject, along with the shaking of heads. 
Anyway, he connected the laptop and had a look. His program was not a triumph one but a general diagnostic thingy. He could not adjust anything, but, he did say the problem was "probably" a throttle sensor issue.
What i would like to know is, are these little blighters prone to going tits up, and are they easy to replace?
I would like to add that my local dealer is over 70 miles away and I need to sort this little %$&* before the weekend as I am hopefully off to Italy next week. Some hope!