In future, please make your title more descriptive. I've edited it for you this time. Thanks.

ps. By any chance have you warmed up the engine (3 bars) before you try to drive it hard? You say you've just put in new plugs. Check all the coil pack wiring harnesses. You may have one or more clips not secured tightly.

 

Thanks for the quotes people, i did the MAP Whack, i'll see the result tomorrow, a friend of mine told me i should get my fuel filter changed, what do you people think of this? When i bought my car it was at 34k Kilometers, now it's 41K Kilometers. I first used normal petrol 90-95 octanes, now i use 100 octanes 5 star!
What else might be the reason of my problem? what should i do? Please help!

 

give the map sensor whack a chance first, as it is much easier and does not cost anything. It is relatively low mileage to have a clogged fuel filter but anything is suspect at this point, and if its not too much trouble you can try changing it out. In most cases, the filter is clogged and usually doesnt work at all rather than just on/off but you cant rule it out.

 

I tried the MAP Whack, i'll be testing that in the next 24 hours, i'm gonna get the fuel filter changed, i'm going to order a new one on tuesday, i hope my problem will be solved, but please if theres people who experienced such a problem like this please help me find the way out of this!

 

I think the MAP Whack didnt work, did the thing again today,
for god sake help me it's driving me crazy

 

I know I'll get flamed for saying this, but maybe its the fuel? Why not run the recommended octane (91)... 95-RON I believe.

Running a higher grade of fuel really provides just about no benefit for a car that isn't tuned to take advantage of it

 

I have only the exhaust modified (exhaust manifold + system) but i still have the catalytic convertor. I use 100 octanes because some friends of mine reccomended it for the best performance, i have 5 friends here who has s2k's, there's only 7 in my country by the way, them all use 100 octanes and it gives perfect performance really. I did try 91, 95, 98+ but i think 100 is the best.

 

All I'm saying is that the ECU isn't tuned for 100 octane. You're basically paying extra money for nothing

 

Only other thing I can think to do would be to buy an OBD-II datalogger. Leave it plugged in and when you experience the problem, go back and check the logs. See if the ECU is pulling timing or something, and if so, maybe you can determine why.
Maybe you have a bad sensor somewhere. Who knows... but this might help you find out.

BTW... I do think the fuel system is a good place to start. You've already verified that the injectors should be OK. Replace the fuel filter... if that doesn't help, check/replace the fuel pump.

Also, what is the air temperature when this occurs (in Fahrenheit degrees, please!)? Has the car been parked, idling, or stuck in traffic or does it happen when you've been cruising down the highway a while?

 

Do you not have a different octane rating system over there? In N. America, we're supposed to use a minimum of 91 Octane. For you, isn't this a much higher number? Isn't this closer to your 100? If so, then you are running really bad gas. Not only could it be low octane fuel, but could it also be that it's really DIRTY fuel? Just another idea. If you are running octane that is too low for this car to function properly, do you have octane boost? If you do, maybe try some to see if this makes any difference.
When you change the fuel filter, inspect it to see if indeed you have been using dirty gas. Also, you guys DO run UNLEADED fuel, right? If you have been using leaded fuel, your catalytic converter is most likely completely clogged.