Possible Low Load/RPM knock?
 

This has been bothering me lately so I would like your guys' input. I have been searching for a looooong time and I just would like to see where I should hear towards my diagnostics.

First off, the car has always done it a bit ever since I bought i with 24k miles on it. I now have 30k, and it has never gotten worse, but not better.

The "knock" sounds like it comes only from the driver side of the engine, and when I have more weight in my car. This would usually mean more weight = greater load on the car when the knock happens. However the knock only happens at low rpms, between 1300 - 2k rpms, mostly at 1600. It also happens when I am not WOT, but driving gently, and normally. I find this very weird.

I have good oil pressure (45psi - 60psi)

Stock internals.

Bolt ons (LT headers and true duals.)

I know there are 100 things that can cause a knock like sound and am not sure what steps to take first/what it could possibly be with these weird conditions.

I know what a rod knock is... a Saturn we used to have was about to throw a rod and it was so loud even at idle. This sound resembles it and but is very faint most of the time. I even picked up a friend for the added weight today and drove it around and I started to hear it eventually after driving for 15 minutes (when it wouldn't do it at all till then, and it was still barely noticeable by me, and he didn't hear it because he doesn't know the car like me.)

I know is I had 2 others in the car it would be louder. I even put it in 4th gear at 20mph and gunned it in that gear to get a large load on the engine but no dice. But in 2nd keeping the rpms constant at 1500rpm there it was.

I was about to cam my engine but now I want to make sure what this could even be.

So far it could be:

-EGR issues
-Exhaust leak (doubt it)
-Timing chain
-Valvetrain (doubt it)
-rod knock or bearing wearing out (freaking hope it is not)
- a lot more i forget.

Do these symptoms even make sense?

Are you sure your clutch isn't slipping?

Do a search on the topic "piston slap" and from that information, compare your symptoms. HTH - Mike

Yes it still grabs. Keep it mind it does it mostly while on light throttle in even 1st and second gear. The 4th gear pull was just an example to show that a heavy load was put on the engine in hopes to amplify it, to no avail.

I definitely did that many times, and it occurs when the engine is mainly warm. aka it does not go away once the engine is warmed up.

Yeah I don't know either... lol.

Another thing to add to the list of diagnostics is from where the AIR bolts up to the headers? I hear that can make the sound?

Mine is doing the EXACT same thing, knock at 1600/1700 rpm second gear light load. Wont do it in first gear light load but if I PUNCH it in second there's no knock at all.

Right now my car is throwing a code for the drivers side CHECK valve P1415, so I dunno how that would be it, but I'm about to go to autozone and pick one up.

Did you fix yours?

Mine is doing the same.

Under heavy gas, no knock, take your foot off the gas, any gear and as it's coming down bam there it is.

It doesn't happen when cold or after I've been on the highway, only when i'm just taking it easy. However tonight I did get it to do it after a drive if I held the throttle open at 1500 rpms.

Funny thing is I had a check valve code thrown a few months ago, for the drivers side. The light went off and I never replaced it, lets hope that's it. I'll replace it tomorrow.

Did you guys ever figure out what it was?

So the sound is coming and going, I hear it ALLL the way home, rattleing all the way home. I pull up a hill into my driveway and I cant get the car to make the noise.

Pissed, I pull out into the street. And start driving. It makes the noise like crazy. I stop at the stop sign and rev it, there it goes again (not moving, clutch in) I take it out on the main road and get it nice and hot. Ok we've got a solid knock now, 15 seconds later I pull into my driveway (up a slight hill to a level landing) and of course, it wont do it again!!! WTF-

dead thread resurrection.
anyone ever find an answer to this problem?
I have the same thing going on.