Where's the Horsepower?

[chevy0071]

are you referring to the fuel management where it cuts off and run in 4 cyl?

No, I have checked the "screen" that shows when you're 4 or 8 cylinder, and it doesn't switch according to the screen.

Yes, the shutter is good word to describe it in the RPM's listed above.

---------- Post added at 09:28 PM ---------- Previous post was at 09:04 PM ----------

I have experienced this.
Slight shudder only when my converter locks up and a little chop in the idle at stops. The vibration at stops sounds like it could be a misfire. If I remember correctly, mine does it at the same rpms as yours. I'll have to check that in the morning.

This is exactly it. Is this normal?

---------- Post added at 11:09 PM ---------- Previous post was at 09:28 PM ----------

Ok, so after looking at it again it might actually be the AFM System. Is there anyway to disable this? If it takes a tune, can you do it with a Diablo tune?

 

[ccapehartusarmyINF.(ret)]

what rear axle ratio do have

 

[chevy0071]

what rear axle ratio do have

I have no idea, but I turned off the AFM tonight, and that seemed to help so far. I only drove for a little bit, so I'll know tomorrow.

 

[rumdogbiker]

What you describe is exactly how our 'new to us' 2010 LTZ acts. I have been trying to convince myself that I'm just not used to the 6-speed trans, and am feeling uncomfortable about what feels like a bump in the idle, like its missing. I don't know, maybe it's fuel management...... One thing I do know for sure, it's a dog.