P0303 Nissan -

Question

My 2003 Nissan Altima service engine light keeps flashing as I'm driving also my car shake, lack of power and funny fume smell , I put the machine and I got this p0303

Answer 1

if you have not done to tune up (replaced the spark plugs) I would do that first. 

if the problem is still there the ignition coil might be bad, I would swap a coil with a different cylinder and see if the code goes to the other cylinder you switched with 

if the coil is not bad might be an injector or worst case scenario headgasket