sorry for the repost. I tried to get some feedback in the Maintenance/Repair section and didn't get any. Maybe someone here will recognize this sound..

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

 

Bumping - I am still experiencing this issue. If this is a coilpack issue, would I be able to use UpRev logs to help identify? same if it were some 'other' issue? details on what to log?

The only other thing I can think of is maybe worn down clutch - I have ~60k on my OEM clutch/flywheel. and I do track my car often. This issue doesn't seem to line up with known clutch issues that I have read though..

It does seem to occur more when the car is cold..er.. not warmed up.

*only other update is that p0037 and p0057 have been resolved with new sensors.

 

I think i can hear what you're referring to, i'm going to take a guess at a joint/gasket somewhere that's leaking. Expansion causing the gap to close when hot.