What is this part ?

[holmesnmanny]

http://www.utoyot8.com/FullImage.asp...8-++++%292VZFE

The top left corner 17650 VSV(vacuum switching valve). Mine was originally broke so I previously pulled one from pick n pull and put it on but I never did find out what it does. It is attached via a scew to the RH bank valve cover.

[nopain00]

I believe that's the fuel pressure VSV. It raises the fuel pressure during a hot restart. Usually the fuel pressure is low when the vacuum is high (like at idle), and high when the vacuum is low (like at WOT).

During a hot restart, the ECU supplies voltage to the VSV, which vents the vacuum to the atmosphere, which "fools" the fuel regulator into supplying higher pressure.

With all this said, you can have a hot restart just fine without this valve operating in most conditions, though the starts may take a tad bit longer.