Well for as long as I can remember my MPS6 would hesitate 2-3rd gear change on WOT, for a blink of a second the motor would stutter 3 or 4 times before going back to full power. This was extremely frustrating because for all the power the car has you had to ease the throttle in after changing gears.
Yesterday I had had enough and went searching for an answer (again!!!)
I came across a link that was mentioned in this forum and I read the 24 or so pages and then decided to give it a go...
wide open throttle engine studder FIX - Mazda 6 Forums : Mazda 6 / Mazda Atenza Forum
It only took 20 or so minutes to complete the mod and the test drive after was amazing, full power with no hesitation at all. I tested it on flat road take off, an up hill highway that I know it always hesitated on and with DSC on the off. Plus as soon as I turned the key you could tell the car idled smoother as well!!!
The mod requires you to take off the TMIC, unplug each coil pack and take them out one at a time. The coil plug will split in half by pulling the rubber extension away from the hard plastic top. Once you have done this a spring about 10cm will be able to be removed.
This spring links the coil pack with the top of the spark plug. The problem seems to be that the end of the spring that reaches to the spark plug leaves a gap of about 4mm.
Once you have the spring out it needs to be stretched, stretch the last 1/3 of the spring that is going to touch the end of the spark plug, this will make sense once you see the spring. Stretch it about 5-6cm just using your fingers to pull it apart. Once you have done that stretch the middle 1/3 (thicker bit) out by a 1-2cm. Now the spring has been stretched pop it back in the rubber extension and push the coil top back on to the extension. You will now notice the spring reaching further to the end of the rubber extension where the spark plug will slip in to. Lastly before you reinsert the coil pack back in position use a flat head screw driver to scratch (score) the top of the spark plug (no need to remove the plug) this IMO just makes sure you get the best connection between the spring and the top of the plug. sit it back in position, bolt it down then click in the harness.
Repeat this to all 4 coil packs, then put it all back together and test drive
Although this procedure can sound complicated once you see what I am talking about it will be no problem at all to figure out, like I said it took me only 20 mins or so to take off the intercooler and do the mod and get it back together.
This info has been on mazda6club for over 3 years, I only wish I knew this before today lol!!!