Where is the caMSHAFT sensor on a 1990 chevy corsica it is cranking over but not starting up, have checked the fule line and am getting presure as well as flow. Took out a spark plug and held to engine and getting no spark.

The fuel pump relay should be under the hood on the firewall, square with a 3 in it. Hope you can read it?

yes a cam sensor will stop the engine and also a crank sensor , engine light on?

crank position sensor/camshaft position sensor/throttle position sensor/fuel regulator//airlock.
How far down the system does the fuel flow? If you have have had the vehicle serviced recently have you had the fuel pressure measured ?

you do not say which engine you have or whether it is petrol/gas or diesel or something else. Please add detail and repost the query.

run the fault codes and check for cam/crank sensors. check operation of immobiliser. check fob key battery
check for ING fuse or fusible link near battery

Have you checked the fuel pressure ?
Is the check engine light on ?

chevy corsica 3.1L crank sensor is located on the front of the engine above the starter.

did you bleed fuel lines

If it has spark, the crank sensor is working. If the fuel pressure is 45psi, that's good.

Are the injectors pulsing controlled by the computer?

Coils and wires are the most likely culprits as they never get replaced hardly ever. You cant really test a coil, you can check for resistance on the plug wires but that doesnt tell you if the insulation is bad on them.

You will have a no start or stalls after engine gets hot and then cools down restarts, the sensor is on the front of the engine mounted into the cam gear cover if it is not visiable get under the, (here is a picture) car and look.