My stock manual 2001 Jetta has an intermittent problem with inconsistent power under load. If I'm climbing a hill, e.g., the car will sometimes lose a bit of power for a second or two and then return to normal power. Whether I'm trying to maintain consistent speed or, more so, trying to accelerate, it'll cycle between typical power and then fade and then typical power again repeatedly. I replaced the turbo for a different problem not that long ago; the injectors are relatively new, as is the N75; I checked the IP quantity adjustor for full sweep and bumped the IQ up to about 3.8 mg (it was just about 3.0 before the bump); the timing is set to slightly advanced. I have an IP case pressure relief valve on order, but I'm wondering if anyone has any ideas of what else I can check. No CELs at present. Many thanks in advance.