My engine makes a sound.

[mykalleems]

Well I have a 2007 silverado crew cab with a 4.8 engine. I Installed some headers , cold air induction , and a flowmaster exhaust. Now when I step on the gas hard the engine clatters and I dont know why? Can anyone help me with this problem?

[Oldgoatherder]

Could it be leaky exhaust? Such as header gaskets or louse clamps. Or is more like a ping because the air fuel ratio is too lean. You would get a check engine light with that and a code from the oxygen sensor. Or is it mechanical sound like a bent push-rod? Does your pickup have a engine driven fan, could something from your cold air kit be hit by the fan? Could the drive shaft be hitting the exhaust?

[mykalleems]

No no and no I have electric fans nothing vibrates. The sound is coming from the engine almost like a rattle but it runs good doesnt smoke good gas miles so Im

[REVNORR82]

I would look for something loose or rubbing/hitting on the exhaust if its a 4wd i know they are a tight fit if its a 2wd its not so tight but still could be rubbing!!

[Oldgoatherder]

What you need is a cheap Mechanic's Stethoscope to track down where the clattering is coming from. I found one Online for like $4.99, other wise you can use a long screw driver, it isn't very safe, put the blade against the engine, and the handle against your ear, then you can hear various noises from inside the engine. Listen around different areas of the engine for the clattering sound. If you can't hear the clattering sound with you mechanic's Stethoscope or screw driver, then the problem is not caused by a mechanical vibration. That would be a sign of an exhaust leak.

[konigandy6]

Does the noise only happen when the engine is under a load? Or if you smash the gas in neutral will it happen too?

How loud is the rattle? Do you feel a vibration when the rattle happens? Does the rattle sound metallic? Almost like something shaking around inside a paint can?

My first thoughts lean right to exhaust. Do your headers have enough clearance. Keep in mind the engine torque under load too.

[pajeff02]

Sounds an awful lot like spark knock. The combination of the CAI and headers has certainly changed the airflow through the engine. Do you know anyone with a scanner that can take a look at your fuel trims? That'll tell you right away if it is an air-fuel issue. What octane fuel do you run?

[Sarge]

Often when somebody first installs headers the harmonics increase significantly...and the good old Chevy Piston Slap becomes much more noticeable.