Series 2 stagea has no ignitor.
Could be anything.
Try harder to explain the problem. Like really try. Be very clear so that we don't have to guess things.
For example, you say when I am sitting still it is rough. Does sitting still mean you aren't moving in your seat or the engine is idling?
Putting the extra 5 minutes into your post will result in a better response that might help you.
Or not, you mentioned you had the plugs replaced, I assume not by yourself. So you either have a huge learning curve to try and fix it yourself or go to a mechanic.