Lag in throttle response...M45

[Tim/M45]

I have gotten used to the throttle lag in my 03 M45, but now my wife is using the car more than myself and she is complaining that it is just plain dangerous at times trying to merge or pass. I cannot argue with her on this point since I have experienced this quite often. Has anyone experienced this and/or found a proven fix for this? I understand this to be a common issue with electronic throttle bodies, but it seams excessive in this case. I have had the car into both of my local Infiniti shops for other issues and am pretty much dissatisfied with their ability to diagnose anything on this car.
I have read about the Pedal Commander as being developed to address this problem. Users of this device claim great improvement in throttle response. At $300 for the device I am a bit hesitant to try it.
Any suggestions are appreciated.

[Ilya]

Us 2011+ guys seem to deal with a similar issue. Would love hear what fellow Y34 owners suggest for you...and if it would work on the newer M's.

One thing you could try is clearing your ECU by way of either device or by unplugging the battery over night or something.

[EdBwoy]

Well, your throttle body is cable operated in the 03. You've got both, but the main system is the cable. I see no need to buy the device...yet.

If you're having lag issues, then it's either a serious loss of power from the engine (like throttle body related as Ilya points to) or a trans issue.
Any check engine, VDC or SLIP lights on?

Does this happen regardless of manual or auto mode? Also does it have a lag when reversing?

[Gene Ln]

I notice the problem quite often myself, however it is always in transmission related applications that I see, for example it takes it quite a while to downshift to accomodate the required throttle/power response. if you are manually down shifting this happens less frequently, however the delay from gear to gear is there always so if you have it in 4th but need second be patient as dropping 2 gears could take 10 or more seconds

[Tim/M45]

Thanks for the replies. Car has 128K miles. There are no CEL's. Nor SLIP/VDC lights, unless I really get on it from a stop. If I turn off the VDC and stomp the gas she has plenty of power. I do love this car. So, I believe it is not a loss of engine power since it does come on strong, eventually. As Gene points out it seems more noticeable during downshifting. When I stomp on the gas to pass or merge I can count off a couple seconds before it downshifts gears. Never noticed this issue in reverse. I have not done anything to the transmission such as drain/fill or flush. Do you think it could be more a transmission issue? When I leave it in manual mode the lag is less noticeable, possibly due to the engine holding gears longer?
I will try to clear the ECU by disconnecting the battery overnight as Ilya suggests.
I did R/R the throttle body a year or so ago due to a high idle problem. The throttle cables are snug too.

Thanks again for the help guys.

[Gene Ln]

Thanks for the replies. Car has 128K miles. There are no CEL's. Nor SLIP/VDC lights, unless I really get on it from a stop. If I turn off the VDC and stomp the gas she has plenty of power. I do love this car. So, I believe it is not a loss of engine power since it does come on strong, eventually. As Gene points out it seems more noticeable during downshifting. When I stomp on the gas to pass or merge I can count off a couple seconds before it downshifts gears. Never noticed this issue in reverse. I have not done anything to the transmission such as drain/fill or flush. Do you think it could be more a transmission issue? When I leave it in manual mode the lag is less noticeable, possibly due to the engine holding gears longer?
I will try to clear the ECU by disconnecting the battery overnight as Ilya suggests.
I did R/R the throttle body a year or so ago due to a high idle problem. The throttle cables are snug too.

Thanks again for the help guys.

This is only my opinion but I think it has to do with the way they designed the traction control system, that and they didn't want the full engine power slamming into the drivetrain so they have it ease in. the only real option would be to reprogram the electronics, and or update to a new transmission that handles these better. I have learned to live with it, couple things I do is turn off VDC and use manual when required if I forget to before hand I just live with it

[EdBwoy]

Well, guys I'm gonna have to test this when I get my 03 back from the shop. I would say it sometimes has an Infiniti kind of lag when I stomp on it and it's around 4th gear in city driving, but nothing dangerous... the engine is always eager to jump RPMs like a hot rod, but the trans seems more modest.

In fact most times I just leave it in auto mode, VDC on and I still walk away from most cars on the highway. Even in traffic, it's got a very strong creep if I let go of the brake pedal.

But I'll deliberately test it next time I'm in it.

[Ilya]

Yeah, I live in manual mode like 99% of the time. Sometimes I forget I'm in D when I think I'm in M and I accidentally pop it into N lol.

[EdBwoy]

As I mostly remembered it guys, nothing unreasonable in the way my car responds to throttle input. I recorded video; is this similar to what you see?

The first half is in city driving, second part on the highway. The 08 M45 has the same kind of delay. One thing I didn't do was to blip the throttle to around 4500 RPM like you would in a manual transmission. IIRC, that seemed to drop gears quicker and get in you in the power band. The 06+ cars do the throttle blipping for you so you just keep your foot planted.

[Gene Ln]

I don't see it much on highway cruising, but most of my daily commute is city stop and go, 45 mph is the usual fast speed.

[Gene Ln]

For example where I see it most often is if I am going to change lanes and im crusing between 30-45 mph with the stick in D I turn the wheel and stomp the throttle to quickly merge over there will be a 3-8 second delay. depending on how fast I am going the delay is shorter or longer as the trans has to down shift once or twice.

[EdBwoy]

So pretty much like the first part of the video, or unlike it?

So you're saying there's a delay in the trans shifting or is the delay in the car getting to speed?

[Gene Ln]

the delay is in the trans shifts. once in the correct gear, either via manual, or just right speed/right time the car takes off like a scalded dog

[Tim/M45]

My issue is pretty similar to what Gene describes above. Mostly noticeable at moderate speeds when engine is in low RPM range and I floor the gas to pass/merge. It seems like the delay is more in the trans downshifting than in engine starting to rev up. The delay, or lag, can be several seconds or more and sometimes it seems like it isn't going to happen in time to avoid a collision. When the engine is not fully warmed up this does not seem to happen. In fact, she seems to have considerably more pep before getting to up full operating temperature.

[EdBwoy]

Ok, so what I'm gathering is that y'alls 03 m45s have issues finding the right gear.
I mean sometimes in cars you punch it and they can still take off in top gear, but the y34 almost always down shifts if you lay your foot down aggressively. And yes, it does sound dangerous at this point.

When the engine is not fully warmed up this does not seem to happen. In fact, she seems to have considerably more pep before getting to up full operating temperature.

Good info to have. Not sure why it does that, but it's a starting point to think about.