Right after the first engine start of the day when it is still cool, if I give my car some gas I get this stuttering/missing type sound from the exhaust. It seems more prevalent when .. say in 3rd gear going 30 .. and floor it (as seen in the video below). I do get the sound under normal, aggressive acceleration scenarios too - I just did it this way to accentuate the sound for the video.

Engine mods are HFC's, Motordyne MREV2 plenum, 5/16 spacer, UpRev tuned by Dynosty, Motordyne XYZ, shockwave single exhaust.

My only codes are p0037 and p0057 which I've had forever since the cat swap.

The car seems to run fine, I haven't lost any time in the 1/4 mile, when warm I have heard the noise a few times - but in general everything is running well. Just wondering what the heck this is - maybe I am losing some power somewhere and don't know it.

http://youtu.be/iA2pGGWOk6g

 

eh.. maybe I'll try the engine and drive-train section