I've recently noticed that when I'm driving at 40~60km/h and I step on the gas pedal,
sometimes the rpm doesn't correspondly increase; instead it falls down around 500rpm for half a second, than starts to increase.

It is as if the engine didn't get enough power or gas to increase the rpm as pressed,
or it hesistates momentarily to evaluate whether to kick down a gear or not while letting the rpm fall a little.

Has anyone else have this problem?
Is this perfectly normal? just a gliche with all auto transmissions?
Or is my engine not 'broken in' properly?

 

Maybe because when I press the gas pedal, I'm not in the appropriate gear for the speed,
but not enough pressing pedal for down shifting, so it just hesistatingly and slowly picks up speed..?

 

sounds like a bad fuel pressure solenoid. it happened to mine. everytime i pressed the pedal down, the car would lag and RPM's would drop. take it in for service, the DME reader should tell you what's the problem.

 

Perhaps you should try resetting the trasmission.

1. When the car is off, put the key in the ignition and push the start button without pushing the brakes.
(All the lights should turn on without the engine starting)

2. hold down the gas pedal for aproximately 20 to 30 seconds.
(Afterwards, you should hear a mechanical sound from the transmssion)

The transmission will reset and it will 're-learn' to the way you would like to drive.