Help, Mot failure, High emmisions

[hopper]

Hi

As the title says, my 86 has just failed its mot on emmisions, the garage seem to think its running rich but there not willing to look in to the problem, they said, because its a import and they cant gets parts off the shelve for it and its too much trouble ,

Anyway, i wondered if there are any common problems that are worth investigating?

There are a couple of things iv'e noticed, 1. on the tvis there is a vacuum pipe at the back(i'll put some pics up in a bit) that has blanked off, but its been blanked by double backing a short piece of pipe then zip/cable tieing it up, the pipe has now perished and it just dragging air straight into the tvis.

2. When i accelarate away, from leaving the car standing for awhile, on first 2 gear changes the exhuast is really raspy,kind of sounds like a rally car, then after the first 2 changes that its sounds normal, not sure if that has anything to do with it, but though i'd mention it.

Thanks for any help.

Hopper.