1st Gear shift -> Engine light Flashing

Originally Posted by Cyber370

Normally, a momentarily flashing CE light means you are getting random misfires. It happens often that these random misfires will not give any error codes until the misfires become more prevalent. So, I would take care of it ASAP especially if you still have catalytic converters. Misfires will destroy them.

Start by checking the easy stuff such as spark plugs and coils. Then you can move to the injectors and the rest of the fuel system. Also check for intake leaks.