when I drive the car at around 20-30 percent of throttle, the car acts perfectly fine.. However, once I give it a harder accelaration, the acceleration of the rpm gets slower compare to 20-30 percent of throttle acceleration. It happened to me before, however, I only need to shut off the engine and then turn it on... then it works perfectly again. (only happened like 2-3 time before) Now, it is like that all time...

I have SC in my car, eManage for fuel tunning. My technician thought that it is very likely the spark plugs failure. so, he checked the spark plug and found my spark plugs are all bad. means, I need to change it (about 20K miles usage). However, here in Taiwan, we don't have IK22 or IK24 in stock, so, he put the whatever-spark plugs in for me first. At the very first beginning, the car works ok, but the problem comes back again after 2 days. Now, I am wondering, will any other things make this happen?? any other possibility except the spark plugs? For whoever has the idea what "might" cause this to be happened.. please let me know. thanks