P1200b code 97 malibu

Does it have good spark at plugs, good fuel pressure to injectors and injector pulsing, good cylinder compression ?

Are you missing anything else? Engine cranking, you have fuel injector pulse?
At your ignition coil, brown wire with white tracer, should be hot engine cranking. Probably the same color wire for voltage at your fuel injectors. Use a test light to check for voltage.
If no voltage, check signal from cam and crank sensors. Some of these vehicles the computer has to see proper signals from both the cam and sensor or it won't ground the asd relay. The asd relay sends voltage to several systems including the ignition coil and fuel injectors. Any applicable trouble codes?

I looked at info for 4.0L engine. I don't know what testing you have done?
make sure battery has a full charge, if it cranks good but won't start, have a helper crank it while you visually check for spark at the spark plugs. If spark everywhere, use a gage and check proper fuel pressure, also, check fuel injector pulse. If your missing all three, check cam and crank sensor. Don't replace anything unless your testing points in that direction.
Any applicable trouble codes? What about security system?

To answer the first question, "What does the cam sensor on a 01 Malibu do?": A cam sensor is actually a camshaft positioning sensor.

The Camshaft sensor determines which cylinder is firing to establish injector synchronization and coil firing sequence in DIS systems.

There is also a Crankshaft sensor which sets ignition timing, supply the RPM signal, and determines the engine speed.

The Camshaft Position sensor is typically located in the cylinder head of the engine and has a cylindrical portion that inserts into the head.

The Crankshaft Position sensor is normally located in the timing cover or on the side of the block with a cylindrical portion that inserts into the block.

You can read more about it here: http://en.wikipedia.org/wiki/Crankshaft_position_sensor

I would first check for any OBD codes- and based upon what the reader displays, work from there. You may also want to have a copy of your car's injector circuit and wiring diagram available; along with a troubleshooting and testing guide for same.

Here's a youtube link that gives you some idea regarding a car's injector system: http://youtu.be/JTCgUY51g0s

auto shutoff relay controls both fuel and fire..the parts store can tell you for sure..

Cam sensor? or Crank sensor? I know that the generic definition of DTC P0340 is "No cam signal at PCM" however, a crank sensor can also be the cause of this code.

A cam sensor normally will not cause a no-start. I can cause a long crank time before starting. The cam sensor signal is only used to sync the fuel injectors. If there is no cam sensor signal the computer will start firing all of the injectors on every revolution of the crankshaft to get the engine running. A crank sensor, however, will cause a no-start condition because it is used to control spark. If there is no crank signal there is no spark...period.

Part of the troubleshooting chart for DTC P0340 on your vehicle includes inspection of the crank sensor and checking for the crank sensor signal at the Powertrain Control Module.

Crank sensor has to be bad,or the ignition module.Remove the ignition module and have it checked at the parts store.If it checks bad,replace it,if it checks good replace the cranksensor.The cam sensor,cranksesor,and the control module control injector pulse,and coil spark.I would point more to the ignition module.But I have known the crankshaft sensor to do this also.I hope this was helpful,if so,let us know,thanks,and good luck.

could be, i think i replaced every thing else in the car, so why not give that a go

cam sensor fires the injectors to synchronise injector pulsing with the spark at the spark plugs.. U need to probably change the crankshaft sensor (around the crank pulley) as the crank sensor is what controls the ignition spark.
hope that does it.
:)

Cam sensor fires the injectors so ignition control is not really what it does. The crankshaft sensor provides spark control, the Cam sensor provides injector pulse timing.
The actual code no it throws is much more use for us to diagnose...pls specify the Engine light code and I can be much more helpful.
Why did u change the cam sensor for an oil leak? that does not seem to be an appropriate repair.... anyhow more info=better help
:)