QUIKAG

I have an AEM intake and Magnaflow catback as perf. mods. Anyway, at 4500-5200/5600rpm there is a bit of a rattling noise at higher rpm. It doesn't sound bad, it just sounds like there is something loose clinking around in the engine bay. I don't think it's coming from the engine itself, unless knock sounds like that?

Does anyone know if knock sounds like a very, very light BB's in a soda can kind of sound? It's not a real repetitive rattling sound either, I think it may just be something loose in the engine bay, but not sure. I put premium in the gas tank and have gunned it a few times and the sound is basically still there. I have stock programming too.

Any help would be appreciated!

BlackLM7

It sounds like you have a spark knock (detonation) problem. I was going to ask you about the fuel and programming, but you already answered that. Did you buy your truck new or used? What about your mass airflow sensor in the intake? I noticed you have an AEM. It is possible that the MAF sensor got damaged when the AEM was installed.

BLACKND

iTrader: (5)

Thats what it sounds like, just from hearing your description. I am assuming that you hear in noticably mostly in WOT situations. Kinda sounds like a high pitched pinging noise? Kinda strange because in my experience Detonation usually occurs after programming (handheld) or tuning of some sort. If you bought it used this could be an issue that someone tuned it prior and never reprogrammed it to stock. Other than that, if its not knock, could be some sort of heat shield or something pinging together. I had a similar issue with my 00 Trans Am making a noise, thought it was the rear end or trans, turned out to be a heat shielf between my floor pan and exhaust system, that was loose and bangin against each other.

Other than that, I'm lost, maybe someone else will chime in.

QUIKAG

I've had the truck since new and the programming is bone stock. I'm starting to think it might be a heat shield or something in the engine bay. It does only happen in WOT situations and as it nears the stock redline (5600 1st gear, 5200 other gears). It's not a high pitched pinging noise, it's just a rattling type noise that isn't consistent like what I would think pinging would sound like. It's like someone has BB's in a soda can and they're just barely shaking or swirling them around the can.

Either way, it's annoying as I was worried it was engine knock. Because otherwise the engine sounds pretty glorious with the AEM intake and Magnaflow cat-back. Having that rattling noise is distracting.

If anyone has any knocking/pinging experience, could you chime in and let us know what that sounds like?

Jamesbond2509

iTrader: (1)

That sure sounds like detonation. I had it on my 5.3 and eventially the engine went kaapuut!!! It sounded like someone shaking an aerosol can.
Try some higher Octane fuel, it it goes away it is detonation.
Good Luck

ohohsilverado

how bad is this for the engine. im having to run cheap gas cuz of gas prices and mine does it at half throttle. is this real bad?

Deckhand

iTrader: (1)

detonation is what blows motors up.

Yelo

on a scale of 1 to 10....detonation is a 12

it's BAD !!!!

QUIKAG

That sucks, I'm surprised it's detonating. Shouldn't an intake and cat-back richen up the mixture?

chyboy82

I have scsb 5.3l and I just started noticing my engine making the same noise.
I noticed it after I installed my k&n oem replacement filter, and that is the only thing that I have done to the truck. It only does it at full throttle at high rpms, but not every single time. I was worried so I took it to the dealership today, but they found nothing. My truck only has 5000 mile on it, and I hardly every go full throttle, but this sucks. Not sure what to do, but I don't like it.