Thank God that I'm not the only one with this problem. I tried for a long time to figure out what it was and no one really knew. I even posted vids on here of the car bucking and no one was sure what the problem is. It only started after I put my CAI on. And, yes, my MSP is flashed. I have a 3" custom S-pipe-back exhaust and a custom 2.5" recirculated CAI. I have since spoken with the MSP tech at my Mazda dealer and he said that he had a similar problem with another MSP in town after he had put in a new engine. He couldn't find out what the problem was until he checked out the customers hardpipes and CAI piping. Once he retightened everything he was able to get rid of the bucking.
Right now I have worm-gears on all of my piping. I still have the stock PVC intercooler piping. However, I have purchased two heavy-duty clamps for the pressure side connections near the turbo, and I plan to retighten all the rest of the wormgear clamps this weekend. I hope that this gets rid of the problem. My bucking was so bad if I didn't get off the gas that I recently snapped my left front axle. For the record, I NEVER race the car, NEVER hit it from a standstill, and I NEVER drop the clutch. I DO hit it from a 30-40 kmh roll and this had never been a problem before the CAI and had never produced bucking before. I DO keep my foot steady on the throttle unless the bucking starts and then I get off before the car shakes apart.
Interestingly, it ony happens (as Wiggles mentions) at part throttle, usually in 2nd or 3rd, and at low boost. If I hammer it, I don't get the bucking. I do get some of the typical MSP hesitation despite the flash and, after the CAI, I swear that I am experiencing some bogging/loss of power when the turbo is at full boost. This never happened before the CAI which leads me to believe that something is loose somewhere and precious boost is being spitted out into the engine bay. If it still persists after I have tightened everything then I have to consider the possibility that the intercooler piping has a crack in it somewhere. Should this happen then I will have to go with hardpipes as the intercooler pipes are on backorder at Mazda and the wait time is 3 months!
I will post the results of my service job next week. I also hope my axle gets here soon as the car makes a terrible noise when I am accelerating as it stands right now. The tech assured me that it would be OK to drive for the 2 weeks it would take for the axle to arrive.
R