Yes, It sounds like the float bowl is overfilling and running out your vent. Replace the needle and seat and you should be as good as new.

 

I had the same problem with my 2003 trailblazer. I was told that the motor vibrates in such a way that it beats the carb to death. The floats are shaking so Bad that it is unable to seat. Mine only does it when it is idleling so im just living with it for now until they figure out how to fix it.

 

yes, i would check your needle seats, thats most likely the issue, and be sure to check your floats to make sure there not sticking, there should be pins that they slide up and down on, make sure there not bent, if there bent hopefully there to the inside of the bowel, because they will somtimes hang up on the side if there bent the other direction..