Car stalls and wont start back up.I add a bottle of gas treatment and it starts.Why? I was told it was the crank or cam sensor.How do I tell which?

Need more information. Could be fuel pump, fuel filter, crank sensor, cam sensor. Starter??

you need add more fuel pour bottle gas treatment in fuel tank.replace fuel filter.charge replace battery.you need build up engine compression.remove all spark plugs squirt some oil into all cylinders plugs holes then reinstall all plugs back into engine try crank engine. see what happens.

Here's a link on the camshaft position sensor.Here's the crankshaft position sensor.

usually if the ecu says crank code then its a faulty sensor, can be both crank and cam. as if the crank sensor goes it will not start. cam it will start but not run correctly. low compression would mean eather water in oil, water in cylinders, or blow back on compression. but with all or any of these the engine would still start but run badly.

spray some starting fluid in the throttle body & see if it starts right up & stalls. If yes, then you have low fuel pressure.

If not, maybe no spark. Could be cam or crank sensor. Is check engine light on?

cam sensor,
crank sensor,
theft system

mcdevito75 here, BEST BET, let the shop do this work, too many un forseen problems could come up. The stalling and unable to start for a while could also be a bad ignition module, no test for this part, but I would have it changed, for if it is a bad ignition module, all this other work will not fix the stalling and later start of your car.

you should have engine light on and engine codes
if its the cam or crank sensors, shouldn't be the starter i would start with the ingition switch.

could be either the cam sensor or crank sensor , but I would check the crank sensor first , this sensor will not cause a check engine light either

Have tried getting quality gasoline at a reliable station? It sounds like water in your fuel system. Add a couple bottles of Iso-Heet fuel system dryer everytime you fill up the next few times, and that should cure it.