This is not for the Z but rather for my other car, an Integra.. hope it doesn't matter... but the problem should be the same for all car's suspension..

I randomly get this "thuka thuka thuka thuka" noise, kinda sound like a flat tire when I accelerate from 20mph to 60mph and I can feel vibration coming from the left front tire and also feel it through the gas pedal. This shiet is really driving my crazy and scared to drive the Integra at times.

I recently had my wheels balanced and also my bearings and tie rod checked so that rules out the problem. What else could it be? I was told it has to do something with the clutch that makes the car shake like that... I don't know.. any suggestions? Please help...

 

Have your tires High Speed Balanced to check for Belt Separation

 

The tires have already been balanced but my problem comes and go randomly, it's not constantly.

Say if the tires are not balanced correctly, wouldn't the problem be everytime I drive and not randomly?

 

Whats the skill level of the man doing the balancing ? Belt separation can be diagnosed by a good tire man. Belt separation can be compensated for by weights...that dosent fix the separation, it only tells the machine that the tire is balanced----Apples and Oranges

Random problem explains a little....temperature ranges have effects on intermitent tire probs.

I'm not saying that the problem is with the tires, I'm saying that it is important that you make damn sure that tire malfuntion is checked off the list of possibilitys by a knowlegable, honest tire man. Diagnostics have to follow certain steps, eliminating possibilitys as you progress