loud hum/vibration around 1000 rpm

[gmharrison]

Hi All

 

I have a 2001 Cheve Silverado with the 4.3L 6 cylinder

 

When the cruising around and the rpms drop to around 1000 the engine seems to labour, and the truck vibrates. Increase the rpms to around 1200 and it goes away. Happens at all sppeds the key seems to be if you are around 1000 rpm

 

Any ideas?

[kyle3]

Hi All

 

I have a 2001 Cheve Silverado with the 4.3L 6 cylinder

 

When the cruising around and the rpms drop to around 1000 the engine seems to labour, and the truck vibrates. Increase the rpms to around 1200 and it goes away. Happens at all sppeds the key seems to be if you are around 1000 rpm

 

Any ideas?

 

<{POST_SNAPBACK}>

 

 

There is a TSB for this problem. The fix is a flex coupling in the exhaust pipe it solved this same problem on my 2004 4.3

[drumset5994]

Also, check your rubber exhaust hangers...mine rotted and made it worse...they're about $2.49 at Autozone a piece, i put two on each hanger to replace, because they were thinner than stock. Cleaned the vibration right up.