There is this screw on my fuel rail, and it comes off about every 2 weeks. Anyone know what this screw is for? I'm worried that gas might come out of it and is causing my car to bog sometimes...

 

i dunno what that screw is for, but if you want it to stop backing out put some loctite on it.

 

thats the fuel pulse dampener. as sayd above just put loctite in it

 

I bought a gsr fuel rail and the dampener screw wasn't there. My existing b16 one worked.
What happens if the fuel pulsation dampener is missing? Will it leak or cause problems?

 

It helps to keep a steady fuel pressure. Some engines have them and some dont. My D15B7 didn't, my D16Z6 does.

 

Should that screw just go in as tight as you can get it or is there a level of tuning for it?

 

It wont leak without the screw. Someitmes they fall out and people drive with them for years and never know it. ANd no it is not adjustable, it is jsut a stop for the diaphram inside. Just stick it in and tighten it. Loctite if it falls out.