Subaru: Problem w/power when cold

I have a '91 loyale sedan. It seems that when it's mildly cold it doesn't
have much power , hesitates ( not to the point of bucking ) but picks up
when you try again, and moves better. But it does have a lack of power when
it warms up too, till you get past 3/4 peddle. Then you hit it to the floor
, and you go like the dickens.. Maybe sparkplugs or wires ? It's only got
83k & the motor has the feel of a new car. Or is it just that it doesn't
have the hp to pull ? Is there something that I could do to get low end
power warm or cold? Thanks for you help.