My Service Engine Soon light came on the other day. I did an
Easy ECU reset via the gas pedal and cleared it out. It came
on again today, so I pulled over and cleared it with the pedal
method. So I think I'm going to replace the Stillen AirBox
with the stock one and take it to the dealer. Any thoughts?

2003 TwBlue 5AT Sedan, sunroof,
Graphite Leather, splashguards, HKS exhaust,
14 wire Grounding kit, 350Z duct, Stillen CAI
Underbody rear diffusers, Drilled alum pedals

 

If you've reconnected the MAF sensor correctly and not damaged the wiring, then the SES light is being caused by something else. I doubt the Stillen A/Box with cause a light, but try taking it off and replacing it with the stock box to see if the light returns.
If it does then the dealer will have to retrieve the code.

<font color=red>GSM</font color=red>
<font color=red>GSM</font color=red>
<font color=black>Silverstone Coupe</font color=black>

 

I agree. The light has come on three times now after pedal
resets. I think I'm just going to take it to the dealer. I bet it is
an oxygen sensor or something like that. I just don't want to
get nailed because of having and intake/exhaust modification.
The light remains off for several drive cycles, it came on during
my drive to work this morning. I may not be doing myself any
favors by clearing the light and continuing to use of the G.

2003 TwBlue 5AT Sedan, sunroof,
Graphite Leather, splashguards, HKS exhaust,
14 wire Grounding kit, 350Z duct, Stillen CAI
Underbody rear diffusers, Drilled alum pedals

 

On my way to take the G sedan to the dealer to check out the
SES light, I had to stop and get gas. Wouldn't you know it!
The gas cap was not on the tank, it was just sitting in the
holder of the door. I figured this may be the problem. When I
told the service advisor about the gas cap, he said it would
definitly send a message to the G that something was amiss
and throw on the SES light. He also said the G35 is one of
the very few automobiles that would self clear the light after
I attached the gas cap. He said after several drive cycles,
the G would see the gas cap back on and turn the SES light
off by it'self. This is exactly what happened! By noon today
the G35 turned the light off by it'self.

2003 TwBlue 5AT Sedan, sunroof,
Graphite Leather, splashguards, HKS exhaust,
14 wire Grounding kit, 350Z duct, Stillen CAI
Underbody rear diffusers, Drilled alum pedals

 

Haha, good news. The old -gas cap not on right- problem. An easy fix.


<font color=red>GSM</font color=red>
<font color=red>GSM</font color=red>
<font color=black>Silverstone Coupe</font color=black>

 

All OBD II cars will set and reset with a missing/replaced gas cap.