I have a 2001 focus, 5 speed, no mods. I sometimes have a problem where the car will stumble a bit. Its kind of random but the 2 times that its been the worst were right after taking a right handed turn at pretty close to the limits of the car and ending the turn in 4th gear at around 40 mph. One time was just kind of a light stumble but the most recent was a lot harder, like it wanted to stall. A few seconds later and after dropping down to 3rd all was fine again. Also this seems unrelated but the car stalled once recently at idle, most of the time its fine, sometimes a little rough. What could be causing this?