i'm trying to figure out whats wrong with my Z, it an 05 track model with almost 700 miles on it. it's nowhere near as fast as the performance model i test drove, which had like 250 miles on it. they installed a nismo exhaust when it was delivered to the dealership and i'm thinking maybe that hurt the breakin ? the reasons i think it might be running rich are the black exhaust tips and i'm getting like 15mpg.
i just hope there's nothing wrong with it .

 

when my car was brand new, i got 15mpg also, because the motor is so tight that it is actually taking power to break the motor in. when it loosens up the mpg will go up, and i would imagine that performance will increase too.

Chad

 

I thought that too considering this car had 287 hp. Well, I have 4k and just got an oil change and Ill tell ya its really starting to pick up.

 

Only way to know for sure, is to either install a wideband O2 gauge, or run it on the dyno.

 

i was still getting good milage when i first got my '05 with 11 miles on it...~ 21/26mpg

 

get between 10.5 and 13mpg when I flog it... just got back from DC last night and got 33mpg the entire way back (at 85mph)