Any codes?

Could be bad coil, or perhaps CPS acting up? Did you get any message?


Paul

 

No codes or messages at all

 

It sure sounds like a safe mode. You didn't see any message on the dash besides check engine light?

 

Didn't see anything

 

If it happened at 5500 it was likely DSC/speed sensor related. The sputtering might have just been a cut in power. Just search the 5500 rpm or dyno problems.
You have nothing really to worry about but I hope you actually read for codes as this problem won't light the SES.

 

Turned the car on this morning and had a C5 code for a misfire.

 

Sounds like you may have mafs that are failing have them checked try doing some hard pulls to red line again and see if it will fail safe again

 

The tune I have is hybrid though so it should have bypassed them right?

 

I would check the coils and plugs. Had a similar issues, turned out to be a burnt out and very loose spark plug.

 

If all you have is a misfire code, clear it and drive the car normally. If it happens again, then you've got a problem. A random cylinder misfire can be nothing. In almost 11 years of ownership, I'd had two random misfires happen - neither time was I accelerating fast.

Hopefully it doesn't come back! One thing though - a misfire usually triggers the SES light (momentarily).

 

I should have read your signature I did not realize you were running alpha n, start with basics fuel pressure\volume, spark plugs, mark and move the coil see if the miss fire moves