Need help with friends car

[Danman765432]

Okay my friend does have an import and all but i want to know if you guys can just tell me what it is. I will attach a link to the video for you to listen to it even though it is not that good and you cant really hear the thumping that you do in person. Some background on the car is that it is a 2004 Nissan SER Spec V, 13k miles, header, CAI, and Catback. The car also never went for a tuneup but oil and fluids have been maintained regularly. Never had a problem up until two days ago out of no where. Where it started to have a bouncing idle, stalled a few times, and the engine shakes and makes a chugging sound. To me it sounds like the car is misfiring so i am thinking that is one of the spark plugs. Just want some of your guys opinions.

Thanks for reading and you guys will hopefully have some opinion since you are the car gurus.

My friend also thanks you in advance to since he did want a mustang but for his first car his parents wouldnt let him get and 8 cylinder and also insurance reasons so he is not a total rice ***.

Well here is the link to the video.

http://videos.streetfire.net/video/58a0e624-4889-4b77-bd1c-ccbbb474a383.htm

 

[dragnazz5.0]

it has 13k miles on it? if so, the plugs are probably fine, and if they arent than there is a engine problem that made them go bad. if its running that rough there should be a CEL. go get the codes pulled at an advance auto or autozone and post them up here.

 

[Skoobie]

If it were one of our cars I would say Vac leak. Check the merc and see what its at.

 

[fidstang]

How long after the CAI install before it started doing this. Maybe something during the install got into the intake manifold and made it's way to one of the pistons rings. Sounds weird, I know but, my 89 regal lost a timing chain and a few valves due to a PVC home made cold air induction with K&N cone filter. Bits of the PVC piping burnt off and made it to the pistons. It was a mess when I opened it up. Not to mention my air intake temp. sensor was not in a proper location. DUOOOOO!