Hesitation

I bought a 1990 Taurus with the Vulcan engine about a month ago, I bought it from a 75 yr old lady who probally never went more than 95, but it has 320,000 kms on it and I'm having a problem with hesitation off the line, and it only seems to be about the first 2 or 3 starts after I start driving, and the engine temp seems to make no difference, has anybody else experinced this problem? Also somtimes after prolongued driving my check engine light comes on, only after about 20 or 30 min. and sometimes never, me and my dad just recently changed the steering rack around the same time that these problem surfaced, than ks your time is appricated