Ok, so I used some BG44k in the fuel system, and today the check engine light came on. Stopped into Auto Zone and got a P0303 error. Car doesn't seem to hesitate and actually seems to be running good. Says it could be:

Ignition Error
Fuel Injector
Engine Mechanical

I was planning on putting in new plugs (She's got 62k on her now). Think I should go new coils too?

 

P0303 code indicates that there is an engine misfire. But since you mentioned that car is running smooth and is not hesitating, I think you should reset the code first to see if it comes back. If the same code error flashes again, then first thing to look for are the spark plugs. It would be an appropriate decision to change the coil packs too, so that you can ensure a long time performance.

 

Thanks! Just hoping for some good weather this weekend

 

Turns out #3 was bad after all. Had the shop give me the old plugs and coils, plugs don't look great, but the coils still look brand new. Oh well, its the piece of mind knowing everything is new I guess.

 

Engine light back on- guess I have to swing by the auto store again to get another diagnostic. Can't wait for my VAG-COM to get here. Dunno what it could be. Think a fresh tank of gas might help clear it?

 

Ok, so after the BG 44K the engine light came on and had the error P0303, I went ahead and replaced the coils and plugs, which I probably didn't have to replace the coils, but the plugs were a bit ugly. After the switch, the engine light came back on, but, low and behold, after filling up with gas from a top tier station, instantly, the light went off. I kinda figured that the gas was the issue, so if any of you try the BG44K, let the tank of gas go to just under 1/4 and then fill er up with the good stuff. I will say, I drove to work today (about an hours drive to DC) and I was getting 32MPG! The car is running like brand new. Not bad for a 2006.

 

Okay so the problem was fuel. It's good that you posted the solution. It will help many users having the same issue.

 

Ok, so driving home last night, the CEL came back on. Same issue, Cyl 3 Misfire. Anyone think that maybe its the fuel injector? Is it worth having a fuel injector cleaning service done? I also read that it could be the Oxygen Sensor. Car is running great, MPG is above 31 highway....... Thoughts?