Engine won't rev up freely

[Max Conover]

Symptoms:
- car stalls at low speed w/ ac on during turn
- while accelerating in the higher rev range, engine does not continue
to climb smoothly, but has small dips in rpms as it climbs.

- already replaced knock sensor #2 (code said it was bad) and replaced
bypass valve w/ #108 as per suggestion.

Any ideas.

Thanks,
Max