car sound like having a cam some time

[Killa]

some time car is quiet, and some time in the morning, car sound like i have cam, same performing. sound really good and drive normal though.

 

[Killa]

car idle fine, but some time at while idle at red line, it want to jump forth a bit. it does sound choppy . it run strong as well.should something I need be worried ? it happent same thing when I have bad IAC and idle at 2k rmp, but now it sound the same, but my idle is fine. no jumpy, no drop, no hang idle. any idea ?
only have CAI and full bbk header and x pipe with flowmaster.

 

[Three50won]

I'd say check the IAC, make sure all cylinders are getting the appropriate fuel, air, and spark, and check for vacuum leaks.

 

[Matthew Johns]

my car did that when i first bought it and it turned out to be a vacuum leak. it sounded like it had an e303 and performed well. one day i was looking under there and saw a hose just hanging then and when i found where it went and hooked it up the idle smoothed out and still performs like it did with the leak.

 

[Twista]

Its normal for a stock 5.0 to sound like its Cammed on a cold start. It something to do with the o2 sensors/fuel/air and computer before the car warms up. My car does this on a COLD start. It sounds kick ass like it has a huge cam in it. Soon as i come to a stop the IDLE lops real hard. I love it. Only problem is after like 2 minutes of driving the car is warm enough and it sounds like your normal 5.0 stock engine with exhaust.. not impressive.