I've got an 88 camaro V6 2.8 liter-- Under the plenum just behind the throttle body, there's a black cylinder with an indention on top and a vaccuum line plugged into it. This cylinder is attached to a plate with allan screws. It looks kinda like a spray paint can top. It can't be a fuel pressure regulator, can it? I called GM parts and they said the 2.8 liter engine doesn't have a pressure regulator. Plus the fuel rail goes uninterrupted from the in line filter, all the way to the schrader valve.