Had the 028 TSB applied to update the ECU. Corrected the "hard" shift into 3rd gear I was experiencing and it made the throttle less sensitive from takeoff. What I seem to find now though is a mileage reduction. In short commutes 3 to 4 miles, in city driving conditions, I'm seeing 11MPG. I thought pre-update I was seeing about 13.5 or so MPG. I've filled the tank and clocked the usage - gallons ised and miles driven - 2 or 3 times, the trip computer is accurate - 10.8-11.2 MPG. Granted it's winter blends of gas (not sure that's very different than just adding Ethanol @10% which has been in NY gas for a few years - making Winter Blends no different than other times of the year), but I think that the 028 Update altered something. Comments are gretly appreciated.

 

I have the same problem. I live in Ny and pre flash i got better mileage and the car had more power. I bought my car in feb 08 (07 g35s mt) so i know it isnt the winter blend fuel. Have you heard from anyone with the same problem?

 

NYTECHMALE: I have 07 G35X Auto, brought my car back to dealer a feew weeks after my post, complained that the mileage was down after the 028 ECU update and a bit hesitant when stepping on the throttle. The Service Advisor said the tech adjusted the timing by 2 degrees in accordance with the 028 TSB. He said to drive it for some 100 miles or so, you should see & feel a difference. I'd say there is a slight improvement in the mileage and a bit less hesitant. The 3rd gear up shift is much smoother now (except with a very cold tranny). But I agree with you - it still "feels" a little slower..., but the car is easier to drive in traffic with the throttle less jerky from standing starts.

 

I found just the opposite in terms of mileage.
I've gotten better gas mileage after the update.

 

I also live in NYC with lots of city driving and have seen mileage drop but not as badly as some. From about 17.9 to 16.9, since I had the reflashes done--both 028 and 045(cold start)--as well as slave cylinder recall repair. No loss of power though.

Where in the NYC area did you guys get your reflashes done? Had mine and the slave cylinder work done at Manhattan Infiniti. Their quality and efficiency surprised me.

 

no more hard shift into third??

 

I got the 028 done about 3 weeks ago. My mileage is more or less than same, 18-19mpg. I feel that the car does drive smoother, but it doesn't feel any slower. I'm basing "slower" in comparison to a loaner car I got that was an 08 model. I definitely felt that I had to depress the gas pedal much more to get the 08 car moving. Regarding the hard shift to third, I experienced this when braking slowing down to 30-20mph, then accelerating. It still occurs from time to time though.
I was rather worried about getting the TSB done, I got accustomed to the touchy throttle. Felt like I had power in my hands anytime.