Look around the intake manifold. It probably won't be around the other injectors. It will have a fuel line going to it as well as an electrical connector. The fuel line going to it will connect to the fuel rail. So you could trace the extra fuel line on the rail to the injector.
Not 100% sure about the '87, but there is no PCV valve on the 1986 Volvo 240 2.3L. Flame trap and Oil trap, but no PCV.
It can be a little expensive to replace the EGR valve on the 1987 Volvo 240 DL. The job takes about 1 to 3 hours and can cost as much as about 240 dollars.
Same as any other vehicle ( around $20 in NEV ) unless it is a diesel in which case it will be more than double
I would try a pressure sensitive construction glue such as PL300 for this. Keep it clamped or taped in place for about 4 hours.
The recommended spark plug gap for a 1987 Volvo (all models) is .028"
long answer: yes
The engine valve stem seals are worn. Usually valve stem seal replacement is all that is needed, occasionally there is wear in the valve stems and/or valve guides which requires further repair.
Motorweek - 1987 Volvo C30 27-8 was released on: USA: 26 October 2007
Motorweek - 1987 Volvo XC60 28-34 was released on: USA: 24 April 2009
Motorweek - 1987 Volvo XC60 28-37 was released on: USA: 15 May 2009
Motorweek - 1987 Volvo S60 30-7 was released on: USA: 22 October 2010
Motorweek - 1987 Volvo C70 25-33 was released on: USA: 21 April 2006