My 2003 automatic Hyundai matrix engine vibrates when i accelerate... Anyone can solve this problem?

You may want to get your mechanics to have a look at your engine mounting. I used to have the same problem, even when stationary, I accelerate and engine vibrates. Finally found damage engine mounting.

Does the entire cabin vibrate too?
My matrix used to vibrate too.. initially when I reached 90 km speed and then diappeared above 90kmph.. a year later the problem became worse that the entire cabin also vibrate whenever I exeeded 90kmph. The culprit was the right drive shaft's inner bearing.
If the car vibrate when u enter D or R even when the car is still not moving, most probably problem with mounting.

Yup... the whole cabin, the steering... but only when i reach between 65 to 75km/h. After 80km/h no more vibration. I already balanced my front tires and also changed the wheel bearing and the cv joint. i already spent more than rm700.. really wierd.

I think u should let mechanic take out both of your drive shafts and have closer look.
Some workshops will ask you to change everything and still could not get to the real problem.
I was told to change lower arms and do engine mounting. I did and yet the problem persisted.
Even more ridiculous, some mechanics even suggest to change rims and do gearbox servicing, which I refused.
I finally went to a friends' small workshop in Putra Height, Selangor and he pointed out the problem straight away after driving at 80kmph.
Now everytime my car acting up, I'll go straight to this guy in Putra Height.
I dont trust those big workshops with fancy waiting rooms anymore. Seems like they only know routine service.

so what is the problem that your friend had pointed out??

My matrix also give me this headache. Crusing at 90km/h and below is fine and smooth. But when I accelerate abover 90km/h the whole cabin and steering vibrates. Have done balancing, alignment etc etc.

Had a mechanic to drive my car to check the problem and he told me its the drive shaft problem. Now I'm changing this stupid drive shaft and dont know if it'll fix the problem. Frustrated!

My problem was drive shaft's inner bearing.
But make sure only the damaged drive shaft is replaced.
If not damaged, dont replace. Some workshop will ask u to replace other unnecessary things.