P0300 2001 Toyota Camry -

Question

Car is missing bad when idling. Have changed spark plugs & wires, ignition coil.. Check engine light is on, and blinks at times.

Answer 1

You may have an dirty EGR which may need to be cleaned or replaced, injector issue or ECU if there is no wiring issue.

here are the step below to checking it all 

if the car has issues starting or there is coolant in the oil or oil in the coolant you may have a headgasket problem you can also check compression