My Audi 100 2.2 turbo, type 44, engine code mc2 has created a problem with start up whether its hot or cold, worse when hot.

It takes a while to start and can sometimes backfire just before it starts, when it does start its lumpy and hunts, ever so slight misfire i think.

Once its warmed up its fine but ticks over a little low.

Could this be the cold start valve?

Someone mentioned the thermo-time switch?