could this be a spark wire problem?

Spark plug wires could be the problem. My experience is they will most likely cause a miss under a load, or uphill. Have the wires been replaced before? My thinking is the wires aren't very expensive, so you could "rule them out" as a problem by replacing them. Gary

To me it sounds like you have a spark that sometimes comes too early. I've driven a Toyota where 2 cylinders would sometimes stop working (bent valves) and that went without jerking. What happens if you fill up with a higher octane fuel? A problem with the timing belt would give problems at all times, so I would not worry about that (yet). Did you use the recommended spark plugs?

Do you have a automatic or manual? In case you have a manual, shift one gear down and see if it goes away, meaning you use the high gears too soon (lugging).

I am not sure if I did use the recommended spark plugs. I bought them at Walmart and they weren't very expensive. I know the last set was a lot more. Is there a better set for the 2.2 L engine? I have tried the higher octane fuel and it didn't seem to make a difference. My car is an auto.