I have 2 symptoms of a blown head gasket. First white smoke from the exhaust. Now I have intermittent missfire. How does my car go from working fine to this? I have another thread explaining the long story. Short story is I was on my way home and I got a missfire. No white smoke ever came from this car. It turned out it was a fuel injector and it was replaced. I'm ow I have to all these codes... If someone that knows of these codes and can help me troubleshoot this that would be great. I just hope my headgasket isn't blown I don't have the coolant in oil or oil in coolant and I don't have bubbling coolant when the engine is cold while opening the radiator cap. I do have smoke coming from behind the UIM and back there behind the engine. Ask me whatever you need to I would like to get my car running. I am the one that replaced the fuel injectors. There was a very strong smell of fuel coming from a back injector.

Codes:
Po300( the original code )
Po134
P1320 (newest one)

I am hoping the white smoke is caused by something else.

 

Have you looked through the sticky to find what your codes mean? I think you have the CEL that indicates multiple cylinders misfiring. You could have multiple injectors that have failed open and caused the engine to flood?

How are the rest of the spark plugs looking like?

Look up CarsNToys youtube channel, has a few videos on how to test/verify if your ignition coils and fuel packs are good by testing them with a multimeter. His videos helped me diagnose a misfire i had earlier this year. Take down your measurements and compare them all and report back here

 

I had to replace a bad fuel injector. The cylinder now fires but maybe I messed something up during the UIM removal and install. I have po300, p1320 and po134. I drove the car and it is not missfiring like before has good pick up except now I hear weird noises from the intake like strange and odd whistling noises when turning off the engine. I hear what sounds like vacuum leak but everything is hooked up.

 

So I found out I believe was causing some weird noises apparently the EGR gasket broke and I didn't realize it. I realigned the gasket retightened the EGR and the car runs much much better now. However it still doesn't run at its best still feels sluggish and possibly it backfired on me once. This car doesn't seem to have that same torque it had before this incident. It smells like burning vacuum belts under the hood after it is driven.