How long have you had the car?

If neither you or the friend can find it, maybe the previous owner was an
idiot and removed it.

Since it fits in a large tubing line between the exhaust and intake
manifolds, it shouldnt be too hard to find where it is / is not.

You mean EGR valve... Just look for a big mushroom looking thing with a part
that can be moved up when you reach under the head of it.

Have you all observed that not one automobile has a drain valve installed
to the fuel tank?  Obviously, a drain valve installed at the tank sump
would safely allow the complete drainage of a fuel tank before in-tank-fuel
pump or fuel gauge sending unit servicing.  To the drain valve, a length of
hose would be attached and led to one or more 5 gallon Jerry cans.  Once
drained, the fuel tanks are much safer to work on, although caution should
still be exercised.

Attempting to drain a fuel tank by disconnecting the fuel outlet hose and
attaching a shop pump will drain all the usable fuel, but not all the fuel.
A gallon or more gasoline will be retained in the tank.

Fuel tank drain valves have always been required on aircraft, but totally
ignored for cars.  They are useful for draining water and or other
contaminants.  I am sure that is a useful feature for mechanics trying to
efficiently diagnose or correct a refractory fuel system problem.

There may be a few objections to a drain valve, but there are workarounds.
1. Makes it easy to steal fuel.  2. Vandalism and arson.  3. Accidental
collision damage to valve and resultant fuel leakage. 4. Leakage.   5. Cost
Workarounds are 1. build in key lock 2. build in key lock 3. Locate tank
higher than low point of nearby structures 4. install screw cap as per fuel
injection rail shraeder valve. 5. cost is a non-issue for safety,
particularly on $30,000 plus cars.

A drainable fuel tank makes fuel pump servicing safer than presently;
however, an external pump design is still much safer yet.  One reader
suggested that the mechanic wait until the fuel level is half or less --
good luck if you fill your tank and 10 minutes later the pump quits.  When
the pump quits, the engine stops right now!  Now, if you had a DUAL fuel
pump system, you actually could run the fuel level down.  I have addressed
this issue before: dual pumps, automatic controls, and warning indicators
when one fails.

Think your car is advanced?  There are four self-locking nuts on a Wal-Mart
shopping cart.  They retain the casters.  How many self-locking nuts are on
your $30,000 car.  My car has none that I'm aware of.  Car manufacturers
will do anything to avoid self lockers because of cost. Instead, auto
engineers did their own work-around for plain fasteners.  They specify
torques at least 150% the maximum recommended by fastener torque tables.
Check it out. Every important fastener on your car is overtightened and
overstressed.