Since I've bought my 2010 Silverado I've noticed a weird low vibration coming from the engine at around 1200 rpm, and if I keep it there it does it the entire time and makes the exhaust sound funny. Kinda choppy. Wondering if this is normal, and if it is what is it? My Blazer had a certain RPM that'd vibrate the truck but you could feel it and not hear it. This you can hear and not feel. Kinda feels like an imbalance in the pistons? It's a very quick low toned vibration.

 

everything has its own frequency that it will vibrate. just like a tuning fork. i would assume it is something just as a small rattle if it isnt that noticable i wouldnt worry, if its pretty noticable, check the engine/exaust for witness marks of something fubbing/rattleing. maybe even have someone hold it at that rpm while you walk around the truck and inspect it while its rattling.

 

Well it's not actually a rattle coming from anything, it's coming from the engine. It runs smooth until it hits the rpm then the engine sounds all crazy. Hard to explain, but if no one else has this in their trucks, 2010 or close, it's pretty weird. It'll start revving up fine but if I let off the throttle a bit at around 12-1300 rpm and let it sit there it'll start making this "wobwobwobwob" sound

 

to add onto that, the exhaust makes the "wobwobwob" sound but the engine sounds like if you were to drive on those lines they put on the side of highways that vibrate if you drive over them, kinda like that but slower

 

Look for missing Nuts at the exhaust system where the Y-pipe contects to the intermediate pipe. That sounds just like mine did and I found 1 nut was gone after backing off and the other was right on the end of the bolt. Or better yet if it is under warranty take it back until it is fixed.

 

mine does the same thing its the motor dropping down to the 4 cylinder

 

I have a 005 Silverado with the V-6 vortec engine in it. I had the same noise. Turns out the dealer knew about it. It is a harmonic frequency at that RPM. They inserted a flex joint in the exhaust system that took care of it. I haven't heard it since. I bought the truck new in 2005.