when you have both lights flashing alternately and the engine is cranking but wont fire it means that eng control unit has either wrong or no can signal from Ifz. basically your key is coded to the Ifz control unit and when you put your key in the ignition the Ifz receives that code and verifies it, if it is a matched code the Ifz will permit the engine control unit to function, this signal is sent via the can data bus. i have found that sometimes if you turn the key too fast it will create this exact problem, I assume the coded key cant react fast enough hence Ifz sends no can signal to eng control unit and you get locked out for X amount of time. try turning the key slower to allow for all that data to be processed.