fast idle problem

Hello All.
I have a 1993 v6 3.0litre petrol Triton that no longer produces a fast(warmup) idle on first start anymore. I have not done/changed anything recently and has only 125,000klms up. Any ideas on where the problem might be?
Appreciate any help at all.
Thanks.

Spark plugs and wires.

Like what sebba said, do the basics and make sure all the maitenence is up to date.