Camshaft Position Sensor?

The Camshaft Position Sensor (CPS) is the part of your vehicle that tells the ECM where your engine is with respect to the combustion cycle. This sensor sends a signal to the ECM so that your engine computer will know which cylinder needs more fuel and which one needs ignition. Your car's computer then takes the data given by the CPS, and together with the crankshaft position sensor, it adjusts your fuel injectors' and spark plugs' functions.

On top of that, the Camshaft Position Sensor can also tell the ECM how to adjust your vehicle's fuel-air ratio. For example, if one cylinder in your engine is running rich, the CPS can send data to the ECM, causing it to adjust (in this case, weaken) the fuel mixture in the given cylinder. Without a working CPS, your ECM would have to make adjustments based on estimates—something which could have dire effects on your vehicle's performance.

Now, if your Camshaft Position Sensor is not operating properly, your car's computer might just do the same. The ECM will not be able to collect any data on where your engine is at the combustion cycle, nor can it regulate your engine's fuel mixture. This could lead to erratic engine operation or no engine function at all.