Alright. So I've had this very faint tapping noise (almost like popcorn) at low rpms for a looong time now. It hasn't gotten worse, it hasn't affected performance, and since it's quiet enough that I can only hear it from inside the car between 750-1750 rpms (as in I can't hear it over the engine itself when I'm outside of the car, and once it's revving past 1750ish rpms, the engine noise drowns it out in the cabin), I figured it wasn't anything to be concerned with. I figured it was normal operating noise.I've been doing some research, though,and I've basically got it narrowed down to either noisy injectors, or lifters. Is there a simple way to determine which it is? Can I do the old 'metal rod to the valve covers' trick, and eliminate one or the other?

It just seemed kinda strange to me that I can only hear it from inside the car, and it doesn't get louder/faster (sounding) as rpms go up.

Thanks in advance.

 

well its probably not the lifters since it doesnt get louder as the rpms go higher.if you think its the injectors, you can get a stethoscope, and with the car running, you can listen to the injectors opening and closing, and if one sounds off, then its probably bad or dirty, they should all sound the same.now its not a stethoscope like what doctors use but is similar, it should look like this

 

Or you can use the old screwdriver trick, I'm a poor college student, so that's what I have to go for [&:]

 

Heck, any sort of solid rod will work. We have some dry tinder in the garage that I was trying to use. It worked, but wasn't long enough to really get in anywhere. :P

 

is that what she said

 

Just look out for splinters in your ear. lol

 

Alih: ...no... >.> <.< :P

pete: truth. I was very careful about getting it anywhere it shouldn't be. hahaha

 

Update:

Alright, with this fine weather and me not in a sport season right now, I had a bunch of time to check this noise out further. I haven't picked up one of those stethoscopes, but I was able to find a much longer/better screwdriver to use. After some careful poking around, I've found that it's coming from the passenger side, and isn't coming from the valve covers. It's actually coming from the intake manifold.Also, I've deduced that it does in fact get louder/faster as rpms raise. I couldn't tell this before, because until I could reach this far back, the engine noise would even drown out the sounds coming up through the screwdriver.

Anyway, based on what Alih has said, I'm pretty sure that it is the/a lifter.

But why does it sound so clear through the intake manifold? It's EXTREMELY easy to hear through it.