There isn't an automatic problem with taking the test a third time - but this time you actually do need to lock down a higher score. Three tests all in the same score range *might* say to an admissions officer: I keep trying but I'm not doing what I need to do to improve much, so my score doesn't really change. And that's obviously not a message that you want to send to an admissions officer.
Obviously, you've already maxed out your quant score (nice work!), so all of your improvement will have to come from verbal - and jumping to a 750 is going to be a significant amount of work. You've been studying for a while now but the verbal improvement isn't coming - so we need to figure out what's going wrong.
So. Why the 34 verbal the second time? What did you do between the two tests and why do you think that it didn't work? How did you study - what materials and resources did you use, etc? You may need to try something else.
For example, a lot of people study by doing problem after problem, but they don't spend much time analyzing and learning from the problems that they do - so they don't really learn much. When you review a problem, do you ask yourself these questions:
http://www.manhattangmat.com/articles/a ... roblem.cfmIf not, then you may not be getting enough out of your study. (Note: you don't have to answer all 10 questions exhaustively on every problem, but there are things to learn from every problem - even the ones you get right - and you should be asking yourself an appropriate subset of these questions depending upon how things went on the problem. Get it right? Great - but is there a more efficient way? What are the traps? How could you make an educated guess on similar problems in future? Those are all good things to try to learn when you get something right.
Got it wrong? Why? Your study actions should be very different depending upon whether, say, you knew what you were doing but made a careless mistake or fell into a trap, or you just didn't know what you were doing in the first place. Etc.
Not sure why your verbal score isn't improving? Another option might be to take a class (if you've been studying on your own) or to do a few sessions with a private tutor to figure out what's going wrong and to give you better study methods.
Take a look at the resources in this article:
http://www.manhattangmat.com/blog/index ... -the-gmat/