I have an 06 with 118,000 miles on it, 2.2. I have searched extensively and have not found a problem exactly like mine. I had a code for the O2 sensor and got it replaced along with my transmission cooling lines (transmission was a quart low). Right before I took it in I noticed that the car was stuttering at a cruising RPM. I was worried that it was the transmission slipping and stopped at a gas station and had it towed to a dealership to get fixed. I got the car back and it ran fine but I put a bottle of Heat in it thinking the problem might have been water in the lines as the temp was below zero for a few days that week. It was fine for a few days but the first time I got it on the highway it did it again. It was really bad at first, especially while accelerating up the on ramp but then smoothed out at 65. It stuttered about 4 or 5 times on a 30 mile trip, some worse then others, but happened more frequently when I tried to go over 70. I drive the car to work every day and it doesn't happen very often, maybe twice per trip, but comes back more frequently whenever I take it on the highway. Everything else seems to be fine and it idles smooth. I have held the accelerator around 3000 in Park with no effect. The check engine light does not come on and there are no codes. Also, there is no change in the tach so I do not think it is the transmission or it happens so fast it doesn't register. Right after it skips, the tach rises just a little as if then engine is trying to overcompensate for a stall. Any suggestions would be greatly appreciated. I'm thinking of buying the car a pacemaker and seeing if that helps.