If your car has the 2.5L 4 cylinder engine the crankshaft position sensor is located on the back side of the engine behind the ignition module which is below the intake manifold toward the rear of the engine. You can follow the spark plug wires to it.
If your car has the 2.8L V6 the sensor is located on the back of the engine below the exhaust manifold. It has a single wire and is held in by a single screw. It is in about the center of the engine. The knock sensor is located nearby, but is screwed into the block and has pipe threads.
By back of the engine I refer to the side next to the firewall.
The oxygen sensor on a 1989 Chevy Celebrity is located in the rear exhaust manifold on top about the center.
The MAP sensor on a 1989 Chevy Celebrity is on the firewall on the passenger side behind the strut tower.
The oxygen sensor is in the middle of the exhaust manifold near the firewall.
You can replace the ignition control module and the crankshaft position sensor as required.
The petcock on a 1989 Chevy Celebrity is at the bottom of the radiator on the drivers side.
The mass air flow sensor is in the air duct between the air filter canister and the throttle body on the plenum.
There is no 1994 Chevy Celebrity. The Celebrity was discontinued in 1989, with the exception of the station wagon which remained in production through 1990. Assuming you mean 1984, depending on which engine it is, very easy or slightly difficult.
The speed sensor connector is located on top of the transaxle, passenger side. It is next to the end where the CV axle goes into the transaxle.
The answer depends on what engine you have.
Looking in my factory service manual for a 1989 Chevy Celebrity I found no reference to an accessory relay.
The spark plug gap for your 1989 Chevy Celebrity 2.8 V6 is .045".
The 1989 Chevy Celebrity V6 is rated at 130 hp.