I've posted my issue similar to this in the Idle RPM drop....but mine not only does it on cold starts, but randomly in the middle of the day aswell. Mine idles so low sometimes it cuts off. Dealer cleaned throttle bodies twice no help...then replace the auto air temp sensors...no help...so they've ordered intake valves (actually had to call the tech line to get help because my technician couldn't figure it out) and will replace them next week. This is a big experiment in my opinion but its on their dime. I just hope they figure out what the issue it, kind of annoying.

 

its definitly a tb cleaning.....i am in need of the same thing. Ive taken my car numerous times explaining the same problem to infiniti and they just adjusted the idle which was piussing me off .......now that im about to hit the 36000 mark they told me its the tb that needs serious cleaning after inspection.....finally! I still need to get it done somewhere else

 

Nissan maximas have this issue as well, and I am kinda pisses that Infiniti suffers from it.... I hope to god I don't get these issues, but its disappointing that infinit engineers aren't bright enough to fix it

 

it's sad that they don't realize the cause but there's nothing you can do to prevent the buildup from occurring inside the TB, unless perhaps you apply a teflon coating, which would be resistant to dirt buildup.

 

Yeah but they've got a laundry list of things to check and maintain at the different maintenance intervals. The easy fix is that this should be on that list for something like every 30,000kms. You know?

Ignoring it and having customers in a form post a DIY to do it themselves is not luxury treatment. I think I'll enjoy getting my hands dirty with the car doing it but for the regular Joe who has no idea, it's just pretty crap service.

J

 

So its confirmed that all of these rpm issues are from dirty TB?

 

Hold on... you start the car cold, it idles at about 2,000rpm then after a few seconds you drop it into gear and expect the RPM to stay at 2000rpm still?? Of course it won't.

a) Let the car warm up BEFORE putting it into gear. Let the idle speed at least reach 1000rpm or below and you shouldn't have any issue.

b) The reason it feels like it's going to stall is because 2000rpm is too high once the transmission is engaged and torque converter locked up partially. It will HAVE to drop to keep it from stalling, since you have your foot on the brakes. This is particularly true in winter where idle RPM will be higher to compensate for the cooler water temp at start up.

c) Your throttle bodies are probably fine and have nothing to do with any stall-like issues when the car is cold.

 

Warming up should definitely make the driving smoother in the beginning, but even driving around while the engine is cold, the car shouldn't stall like that... that's just plain abnormal.

 

500rpm is not stalling RPM. The OP was surprised his idle RPM goes below 1000rpm.. IT SHOULD go below 1000rpm, even more so when it's in D and the brakes are applied which increases resistance on the torque converter and thus the engine. Even if the engine is ice cold, you can't have the transmission in D AND expect it to idle at 1500+rpm like it should when it's just been cold started.

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To the OP, does the engine actually stall or vibrate like it's about to stall when the RPM drops after shifting into D? or are you assuming it's about to stall because you saw the RPM drop from 2000rpm to 500rpm after shifting into D?

 

Dude, I don't think anyone is saying that the RPMs should be high when you flip to D. Just that the idle drops really low, low enough that it makes you think you'll stall out. I think we've all driven enough cars (whether you're young or old) to know the difference between something normal and not. I've had six cars in my life, this is the first time I treat myself to a luxury car and it's doing something none of my previous POS cars ever did.

J

 

I don't know about this statement, I don't see why I need to sit there and let the car warm up before I put it in gear. Seems unreasonable unless it's extremely cold, like -20c or less.

Now this is useful technical information. Based on what you're saying, is it safe to say that the idle speed when you're on the brake and stopped should be the same as what it is we're describing? I can tell you that this only happens on a cold start from P to D. It never has felt like it would stall out 5 meters from my home where I hit the first stop sign.

I'll have to read up on what a torque converter does.

J

 

on 2nd gens i know that the serpentine belt provides power (torque, rpm, or whatever it is called) to all the attached components (ac, power steering, etc) could it be possible maybe the RPMs fluctuate when the fan or anything else spins or activates?

 

Read the OP's post. He specifically says "the RPMs drop way down to below 1,000, reaching close to 500RPM". 500rpm is not stalling RPM. Even if the car is fully warmed up and running fine, rev the car standing still to 3-4K RPM and watch the idle drop. It will not drop to 650rpm (ideal idle RPM for VQ35HR) but rather drop a little less and then goes back up to ideal RPM, which is normal.

 

We have 2 electric fans, they will both activate when the A/C in ON, or activate when the car overheats (activate at 100C maybe a little over, haven't logged to see) so I doubt it's the fans, plus they're not abrupt and do not cause a big idle dip when they activate or anything.

 

Need a clarification.... are rpms supposed to fluctuate at all while the car is idle or stopped at a light? or is it supposed to stay at a constant level at all times?

I have a 08 also, and luckily i have not had the car stall on me or physically shake, but during idle or when i am stopped at a light i do occassionally see the RPM drop a little bit before going back up.... but i assumed its normal. Reading this stuff is kind of making me paranoid and notice the RPM behavior more than usual