This happens under anything less than full throttle. As the revs build, right at 3700rpm WHAM there's a sudden jump in power. It's a noticeable push back in the seat. I assume this is the ACIS switching to short runner intake mode. The engine seems to be running fine, but I don't think this is the proper behavior. I feel like it should be a smooth power delivery regardless of RPM and throttle. I've repaired several vacuum leaks, changed the spark plugs, cleaned the throttle body, all the usual preventative maintenance stuff. From my reading, I suspect the oil control valves may be not functioning 100%. Does this sound correct? I've also got a rough idle, not stumbly, but rumbly. What else should I look at?