One time when pressing gas hard, I got check engine code for a misfiring cylinder 2. So that'd be the cause of the stuttering. I want to know can that be caused by a vacuum leak? Another thing is the spark plugs weren't the most expensive but not the cheapest put in, but I don't think after 10k they should failed either way.
Recently my 1999 V6 began to kind of shake when stopped (such as traffic light) with RPM's jumping slightly. The roughness gets less intense when put into neutral but are still there. When accelerating, the car is stuttering and RPM's are jumping around while going up and it shakes too. Spark plugs have been changed within past 10,000 miles.