They are under the cover on the top of the engine. The one that says 24 valve. Each spark plug has its own ignition coil. Be careful when unplugging the electrical harness from these coils, as the harness is known for becoming brittle and having connection issues.
The recommended spark plug gap for a 1987 Volvo (all models) is .028"
spark plug location in a jaguar
spark plug gap is .028
0.30
gap is .028
.30
They should be under the top cover of the engine - no spark plug wires, only some kind of springs that make the contacts.
Underneath the direct ignition. You have to unscrew four torx srews
0.045
.028
.028"
.030