Strange hesitation on hiway

[mxquattro]

Hi guys. I have an '09 G37xs 7at with 142K on it. Never had even a hint of a problem. Routine maintenance at the dealer all the time, and they have treated me pretty well. I got the car with about 30K on it, and the issue Im seeing happened back then too, so this isnt new, Im just asking about it now

- Start the car first thing in the morning, runs great. Get it fully warmed up, park it for an hour or two... then when I drive it again, under light throttle and no load, shifting between 1 and 2 (or is it 2 ad 3?) the rpm climbs before going into the next gear. Doesnt always do it and its not worse now than before, again, just kind of asking about it now.

-Also, whats weird, is heading down a hiway, 80 mph or so, no load, light throttle, suddenly it feels like it loses a little power, the tach climbs a couple of rpm, then a few seconds later all is back to normal again. It is not downshifting. Its done it maybe 5 times in its entire life, so Im not worried about impending failure here, Im just curious to see if anyone else has seen this.

At 130K I got plugs done, belt, filters etc as well as religious oil and filter changes every 3000. I have not had my transmission or diff fluids changed yet but am considering it.

Its pretty nice having a car with 141K on it and having literally zero problems with it whatsoever. I see another one in my future for sure.

[Gilley]

Some G37s have had new programming released for the transmission which fixes some hesitation and shifting issues. See if your dealer has any new transmission programming for your car.

[mxquattro]

Will do, thanks Gilley. When I got it I brought it in to check for any recalls or TSB's and they said no, but Ill try again

[joe603]

How does it idle? Wonder if it's the TB sensors...but that usually is not intermittent. Could also be crappy gas. Try using a different station and filling with premium.

[mxquattro]

It idles like a champ. Whats funny is I almost always put 89 in it because its close and convenient (no, that gas station doesnt have 91!!). But yesterday I went elsewhere and filled up on 91, and this morning on my way in, I felt ever so slightly the same thing but only 1/10th as bad. Im guessing youre right with the gas either being crappy or something like that. This morning it was only maybe 10 miles since fillup so Im guessing if I keep 91 in it, it should be OK. it was in the same place on the hiway too with very similar conditions. Ill pay close attention now to when/where it does it and with what kind of gas.

[telcoman]

Have you inspected your air filters lately?

If you have 12k miles on them perhaps they should be changed?

Yelcoman

[mxquattro]

Air filters were replaced last oil change so maybe 2500mi ago. I will still check though, you never know.

[audtatious]

Wonder if the TCM is having issues....

[mxquattro]

What is tcm?

[audtatious]

Transmission control module

[mxquattro]

Ahhh thanks. Sounds cheap. Im guessing theres no real test for it either, right?

[audtatious]

Not sure...you can go through the FSM to see if there are any troubleshooting steps available.

http://www.nicoclub.com/archives/infini ... nuals.html