I've heard a large number of tuners cancelling these out due to them becoming problematic. I myself had the surging idle of doom.

What benefits does this valve really provide to the engines function & performance? Are there any long term effects to the engines life if it is bypassed?

 

Why would you bypass it? What is the primary function of your car?

 

It increases and decreases idle to adjust for temperature and load. It is vital for daily drivers not necessarily for track purposes