Good to know and makes sense. Thanks.

 

I had the VCS VSC I forget the acronymm related to traction control light and multiple engine codes. I specifically tell them not to mess with the air filter and service it myself now. They unhooked a small air hose behind the filter box that is hard to see that hooks to a metal pipe. I replaced with OEM Denso iridium plugs. I noticed some of the iridium performance plugs have really low milage rating, like 30k kilometers insted of 100k Miles. Just mentioning it because someone could really get a surprise who did not look at the specs carefully. All of the codes cleared up and stayed off after clearning the codes and plugging in the hose and fixing some holes on the hose as well.
ALl of the codes still stayed off but my milage still sucked like 12 MPG to 13 at most.
I had the spark plugs changed, no misfires or codes present and the tech nas mass airflow sensor cleaner from CRC and cleaned the sensor. He showed me before and after and it was pretty dirty. I had recently changed the air filter. Its not related to the engine but there is a cabin air filter that gets pretty dirty in the glovebox. Just a good reminder to do that one too.
The front plugs are really easy to access and change. The rear ones not so much. There are some youtube videos that show how to get to them without taking the intake off.
If you have a really good mobile mechanic you can save on labor if your not doing it your self and not pay a markup on parts. The long lasting iridium plugs will help save money on replacement frequency.
Some people replace the ignition coils. Mine looked to be in good shape and had no misfires so I kept them. They were OEM. Car has about 200k miles.
Now I am getting close to 18 MPG and tank milage improved 60M+ I am running my first full tank that is still 2/3 full. on the partial tank when the plugs were chaned I went from 260 to 320 so I would not be supprised if milage improves even more. Now all my engine lights are off and I suspect when the tank finishes My milage will improve 80 miles per tank.
One other random thought the dye kits work really well on improving the look of the front seats if you take your time with a damp rag to work in the OEM dye on the worn areas.

 

AF Sensor. If you can diagnostic tool and check if your air fuel sensors are bad. Some people call them oxygen sensors, but it's the ones right past your exhaust manifold. There are 2. 1 for each side. Mine were bad and running super-rich and really killing my fule mileage. You could also pull your plugs and see what they looked like. If they're dark in a wet looking it's running too rich.They should be a light brownAnd dry.