RPM dips down then jumps back up when slowing down or braking

F

Fire0nic3FX

Member
Something I've been noticing for quite some time now is when I'm in stop and go traffic or whatever and I push the brake pedal to slow down or come to a complete stop the engine speed (RPM) dips really low for a brief second almost to the point of the engine sounding like it's going to cut off, then it RPM bounces back up to normal cruising RPM speed range. Anyone else have this problem on here? I found a bulletin, but I'm not sure it's the same thing:

ITB10042


  • IF YOU CONFIRM The customer reports any of the following: - Engine hesitation at idle or very low speeds, and/or - Engine speed drops lower than expected when decelerating or coming to a stop. ACTIONS 1. Refer to Step 2 in the Service Procedure to confirm this bulletin applies to the vehicle you are working on. 2. If this bulletin applies, reprogram the ECM. See this bulletin for further detail.
 
Sounds like the dealer needs adjust your ECU/ECM for the proper air fuel ratio at low rpms or it could also be dirty throttle bodies. :smile (2):
 
^might be the problem.

I made an appointment for the dealer first thing Wed. morning. I'll keep you guys updated. Jonas's FX50 does the same exact thing.
 
How many miles on your FX Aaron?

Subscribing to thread to hear outcome at Dealer. Always informative and helpful threads when you post
 
A car's made for driving right? I got a ton of miles on mine as well.



Rooted Samsung Galaxy S2 on
 
a dirty throttle body can cause this on the first gen DE, eventually it can even stall and start back up fine. the HR has dual throttle bodies but they could be dirty... I'd check that first
 
Fire0nic3FX said:
Just hit 40K a couple days ago haha. Why?
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I was just wondering in case this problem you are having crops up after so many miles. I only have 47,000 kms on mine so far. I put more mileage on my other vehicle/year.
 
GEE35FX said:
I was just wondering in case this problem you are having crops up after so many miles. I only have 47,000 kms on mine so far. I put more mileage on my other vehicle/year.
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This has been doing it pretty much since day one. I just been ignoring it cause it does it randomly. I'll bring up the throttle body thing to them even though it's been cleaned before.
 
i had the same issuse on my 50 .....after letting my mother use my car for a week while away at work ....took it to the dealer yelled at the service lady they reflashed the ecu and the problem went away. ( i was only rude to her becasue she kept on telling me its normal, now everytime i take my car in she get the head tech to talk to me)
 
dwaynedadon said:
i had the same issuse on my 50 .....after letting my mother use my car for a week while away at work ....took it to the dealer yelled at the service lady they reflashed the ecu and the problem went away. ( i was only rude to her becasue she kept on telling me its normal, now everytime i take my car in she get the head tech to talk to me)
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Dealers usually give the run around that this is normal and thats normal. Hey do you have a copy of that invoice that shows which ecu reflash they did? I would really appreciate it if you could let me see that way I can tell the dealer that other people have the same problem.
 
I wonder why dealers do that...just do the work and get paid....who doesn't want work these days!

Wayne---I started noticing mine more and more later versus earlier, but maybe because after i noticed once I pay much more attention to it. I bet you have the same...maybe not. It's hard to notice. When you come to a stop, the rpm dips slightly....I notice it once every now and then.
 
I haven't noticed mine doing that, but then I never paid close attention to it. Next time I'm out I check it out.
 
I knew I wasn't the only one experiencing this! I thought it was related to the already hard downshifts with the transmission, but it's not. Because when the RPM dips down when slowing down it almost comes to a point where the engine acts like its stalling or wants to cut off, then all of a sudden the RPM jumps back up to normal.


Looks like the FX isn't the only one with this issue. Infiniti released a TSB the other day with a similar issue on the 07-08 G35 sedan and 2008 EX35 except on them it's so bad the engine actually shuts off:


[h=2]ITB11018: 2007-08 G35 & 2008 EX35; Engine Hesitation/Stops Running at Idle/Low S[/h]
  • IF YOU CONFIRM The customer reports any of the following: Engine hesitation at idle or very low speeds, and/or Engine speed drops lower than expected when decelerating or coming to a stop, and/or Engine stops running at idle or very low vehicle speeds (parking lot maneuvers), but can be restarted. NOTE: this incident may occur immediately after an oil change. ACTIONS 1. Refer to Step 2 in the Service Procedure to confirm this bulletin applies to the vehicle you are working on. 2. If this bulletin applies, reprogram the ECM. See this bulletin for further detail.
 
ill have to look for it did it a while ago sorry ....if i dont find it i will have them print it out for me when i go back to them.....

Fire0nic3FX said:
Dealers usually give the run around that this is normal and thats normal. Hey do you have a copy of that invoice that shows which ecu reflash they did? I would really appreciate it if you could let me see that way I can tell the dealer that other people have the same problem.
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---------- Post added at 11:49 PM ---------- Previous post was at 11:40 PM ----------

maybe you ask to nicely now i just go in with a list of demands and my facts and proof to back it up and they do what i ask i even made her look at the tsb section on here twice.

jdTrader said:
I wonder why dealers do that...just do the work and get paid....who doesn't want work these days!
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Went into Infiniti of Massepequa this morning and told them that the RPM drops down when slowing down and braking and then suddenly bounces back up to normal. Provided them the TSB number and technician test drove the FX and I guess found the problem. I was told they had to contact Infiniti headquarters about this issue and they told them what needed to be done. Must be really common thing then. They reflashed the ECM and did throttle relearn and idle air volume relearn. Drove about 50 miles in stop and go traffic today and problem seems to have gone away!!! I'm do happy. My stops aren't jerky anymore like was they use to be. I use to slow down and come to a stop and the car would almost stall and give a slight jerk when it did that RPM dipping thing. Well no more!! :)

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