It screws into the intake manifold next to thee thermostat housing.
Under hood, passenger side, lower engine area, front of starter, mounted in engine block.
The idle sensor on a 1991 S10 4.3 can be located at the engine bay.
Gas sensor? Not sure what you mean, could it be a Fuel gauge sensor? Oxygen sensor? Fuel pressure regulator?
behind the bottom pulley of the engine
If it has a 4.3L engine the temp sensor is located next to the thermostat housing.
intake manifold vaccum leak
The 91 has the 4.6L engine and has a MAF sensor located just after the air filter box so it has no MAP sensor.
rear of engine compartment near the bulkhead
it is located on the firewall side of the engine to the left of the oil filter
The 1991 Acura Legend does not have an oil temperature sensor. It does have an oil pressure sensor. The oil pressure sensor will be located on the left-hand side of the engine.
The coolant gauge temp sensor is a one wire sensor located on the right rear of the engine block.
The only engine speed sensor is the pick up plate in the distributor.