I just had it done yesterday, they re-programmed the ECU. It made a HUGE difference. Not only does the cruise work correctly going downhill now, but all the annoying little hesitations, stumbles and surges under light throttle are gone. It's much nicer and easier to drive now. This fixes the one thing I really did not like about the G35. Highly reccommended.

 

Tranny still bang when going into 3rd using M mode?

EDIT, just saw you have 6MT. IGNORE.

 

I hope that all the little tranny issues (bumps, hiccups & jerks) are fixed with this re-program. I posted a thread about my tranny issue going into 3rd gear. Do you think this will be fixed as well?

 

I can't say because my G35 is a 6-speed manual. However, when I first mentioned the surging to the service adviser, he said they would make some adjustments to the transmission controller (um, that would be me......), then he realized I had a 6-speed. So there may be something they can do.

I would get the TSB done (assuming it applies to your car, see TSB in FAQ section) then go from there.

 

I also had this TSB performed and agree with bkrider. It also seems to have resolved the problem that 6MTs were having as described in this thread:

https://g35driver.com/forums/showthr...ght=hesitation