I also have this annoying flatspot/hesitation or whatever it is. After reading this thread and repeating it elsewhere, someone informed me my EGR doesn't have a vac solenoid and on checking the car (and Haynes) I see he's right, it's opened and closed by a stepper motor. In my case, I plan to remove and clean my EGR as there's a lot of soot deposited around the cooler that needs fixing too, otherwise I have no idea what else could be causing this problem as it's not confined to low rpm (it'll manifest around 3krpm if I apply more throttle and hold for higher revs before gear change). ie, it seems to correlate more to the brief "off-throttle and back on-throttle" period when changing gears, rather than a specific rpm zone on acceleration. Additionally, in #28 re the assertion "The egr valve should only work when warmed up..." etc. I was prompted to check this as I was sure I've seen live data from my EGR before it was fully warmed up and sure enough found out I was right. Okay, we're in the middle of summer but I have a recording showing coolant temp on startup was 16C and the EGR was being commanded to open almost instantly. It's certainly fully active from cold.