I received a P0340 on my 1995 Nissan Altima. It says I need to replace the Camshaft sensor. The dealers say that my car does not have one in it and that it may be in the distributor itself. Is this true. Do I change out the entire distributor?

They may be right. I cannot find the part. here is what the manual says:

REMOVAL & INSTALLATION The camshaft position sensor is located inside the distributor. On some distributors, the camshaft position sensor is not serviceable (replacement parts may not be available separately). If the camshaft position sensor is serviceable, use the following procedure.

1. Remove the distributor cap and wires.
2. Remove the rotor.
3. Remove the camshaft position sensor cap.
4. Remove the camshaft position sensor mounting screws.
5. Carefully remove the camshaft position sensor.

1. Position the camshaft position sensor in the distributor and tighten the mounting screws securely.
2. Install the camshaft position sensor cap.
3. Install the rotor.
4. Install the distributor cap and wires.

The distributor in the 95 Altima contains an optical sensor with slotted disc to output timing signals, it's not a replaceable component so the distributor needs to be replaced to fix.