Wow, you are actually too lean. Considerably too lean. You really should be in the high 11-12.00 range. Do the guys who tuned your car realize that? It needs to get more fuel at rpm. What octane gas are you running? Being in Las Vegas, you are at a little elevation (around 2500') and you can probably get away with it without detonation as long as your timing is conservative and you are running 93+ octane gas. If you took it to LA and were running 91 octane, I bet you'd get some detonation. -And you might get some in the heat in Vegas once summer rolls around. I would tell the guys who tuned it that it's a little lean and you'd like the a/f ratio a little lower. And find out how much total timing you are running. I'd like to see an 11.8 a/f # and your total timing set depending on the octane level of gas you run. 15-19 or so, depending. The bottom line is that I don't want to see you damage your investment.