Quote:
Originally Posted by Wires
The issue is it runs REALLY lean all the time. That "lumpy" idle is just a bi-product of the ECU trying to maintain idle at an AFR that an engine should never run at. 
Perfectly normal. My 2008 GMC does the same. I don't remember my n54 having as much shutter though, but I believe it ran a bit richer than the B58 does. |
There are so many factors that go into the "smoothness" of idle such as ignition timing, cam timing, AFR, RPM, injector pulse, rotating assembly weight, motor mounts, etc. This really has nothing to due with the size or power of an engine. There are other variables that could contribute as well. To put it in simple terms, pretty much any modern engine can idle as smooth or as rough as you want it to, its just a matter of what the computer tells it to do.