My 2003 pt crusier stared jerking and the engine light came on. what could cause this?

You need to get the code that caused the check engine light to come on. Put the key in the ignition and turn the switch on and off three times... after the third time the code, P followed by four digits, will show on the odometer screen. Or, you can use a code reader machine to get the code. You can then Google that code to find out more about what the cause is.

Steven and I agree 100%, he is right on and when you get the code: http://www.ptcruizer.com/computer-codes.html............is a list of what they mean

my 2007 did the same thing, it was the camshaft position sensor, part is 35.99 to 54.99 on line and in parts stores,