If you have sparkplug wires, you have the lost spark system. The camshaft position sensor is located under one half of one of the coils and is just a capacitive plate that lets the computer know when that side of the coil was firing on the compression stroke vs the exhaust stroke.
Ummm…no…the car has spark plug wires and 3 coils and what’s under the coils is the ignition module. Cam sensor has nothing to do with that.
Your camshaft sensor does exactly what its name implies, gives information to the engine computer about where the camshaft is in its rotation. The fault could be caused by a failed sensor, a wiring problem, possibly an ignition module, or a mechanical fault inside the engine. Which of these is the issue is fairly easy to determine for a mechanic with basic diagnostic equipment.
It sounds like your mechanic is either unwilling or unable to do any further testing. I would ask around for a referral to a competent local independent garage. A $100 diagnostic should easily get you to the bottom of the problem.