A Little Help here...

I just got a '99 Cobra Convertible...I love it! But sometimes when I get on the gas it hesiates, and sometimes it stalls. The condition lasts until I get home, then when I let it cool down, it's fine. I've driven over a hundred miles and nothing happened, but today, I drove the same distance it it started doing it again. And again, a few hours later it was fine. I think it's the gas I used...Exxon and Chevron seemed to work fine...Sunoco was a no go. I really hope this is not an expensive problem. Maybe like a (sometimes) clogged fuel filter or something. Any ideas?

Thanks

Well, the Ford Dealer is gonna do the 24k service tomorrow...I'l be on a 24 hour shift guarding the skies over the Nation's Capitol, so another soldier from my detachment (he's got a '96 2V Pony with long tube headers, full exhaust, cold air intake and a 4.10 rear) will be taking the car in. Hopefully we'll figure out wassup.