CVT Transmission "lugging" or vibrating at idle

[tc1446]

07 Altima with 2.4 and CVT transmission vibrates or lugs when idling. Give it just a little gas and it smooths out. I'm told the idle can't be adjusted. What should I look for? The air filter is clean and I've run a can of Techron thru to no avail. Gas milage has not changed. CAr has 65K miles on it.

 

[Corvette Owner]

How many miles on the car and have you changed spark plugs (if over 105,000 miles)? Older 2.4 engines (1997) required new plugs at 30,0000 miles.

The Signs That Your Spark Plugs Need to Be Replaced
By Stanley Dankins, eHow Contributor

updated June 29, 2011

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The Signs That Your Spark Plugs Need to Be Replacedthumbnail An electrical current flows through the gap between the two electrodes, creating the spark the engine needs.

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Edmond Berger invented the first known spark plug in 1839. As automobiles advanced throughout the years, so have spark plugs. Some of the advancements spark plugs have gone through include multiple ground electrodes, platinum-coated electrodes and iridium-tipped electrodes. Replacing the spark plugs in any vehicle is a part of basic maintenance. There are three main signs to look for indicating it is time to replace your spark plugs.

Running Rough

A rough running vehicle vibrates on idle or accelerates at a slower rate than normal. This condition can mean spark plug fouling or the gap is too wide. To check if the spark plugs are the problem, remove the plugs and check the gap between the electrodes on the spark plugs or inspect the plugs for build-up -- fouling -- on the electrodes.
Decreased Fuel Economy

With fuel prices steadily rising, it is important to monitor your car's fuel economy. If you notice a significant drop in fuel mileage, spark plugs may be the root cause. When the spark plug gap becomes too wide or fouled, the spark is not hot enough to burn the fuel-air mixture efficiently. This causes a sharp decrease in fuel economy.
Hard Starting

One of the toughest jobs the spark plugs perform is to start the engine. If the spark is too cold, due to excessive gap or fouling, the vehicle may crank more than usual before it starts. Starting a cold engine magnifies this hard-starting symptom.
Checking the Gap

To check the spark plug gap, first remove the spark plugs from the engine. Once removed, use a feeler gauge or a spark plug gap tool to check the width of the gap between the center and ground electrodes on the engine side of the spark plugs. Most automobiles have an acceptable range of gap listed in the owner's manual. If any of the spark plugs have an incorrect gap, replace the entire spark plug set. Some spark plugs are adjustable, but adjusting the gap requires a steady hand and it's typically easier to replace them.


Read more: The Signs That Your Spark Plugs Need to Be Replaced | eHow.co.uk http://www.ehow.co.uk/info_8664757_signs-spark-plugs-need-replaced.html#ixzz1hw8DY7NA

 

[barlowc]

You're sure it's the transmission? What happens if you put it in neutral?

IF it's related to the transmission, you may want to visit your local Nissan dealer. Your 2007 is probably covered by the extended 10-year/100,000-mile warranty. If you're not familiar with the extension, see here

 

[The Critic]

Sounds normal for the CVT. Has it always done this?

 

[Rand]

sounds like a low idle to me.. Does it only do it when engine is warmed up and it is in drive (stopped) ?

 

[Quest]

@OP:

you reported replacing air filter, adding techron into gas, etc. but what about PCV valve replacement? spark plug change (tune ups?)

Q.

 

[qr25de]

It is NOT the plugs. You may want to pull the plugs, inspect and re-grease them at this point though. I doubt the QR (2.5L) in your Altima already needs to be replaced but if it does, it is located on the top of your valve cover. There should be a vacuum line coming from the intake down to the PCV.

While you are inspecting the PCV for proper operation, you can clean out all of the PCV system hoses and check that the MAF and throttle body are clean as well. Depending on how much or how little gunk you have built-up in there, you may need to perform an idle relearn. Idle relearn without the CONSULT is a PAIN IN THE [censored], but you can save paying the dealership pressing a couple of on-screen buttons and charging you $60 or so.

 

[ARCOgraphite]

Is this the engine that eats the converter core? Or was that an earlier iteration?

 

[bladecutter]

Originally Posted By: tc1446
07 Altima with 2.4 and CVT transmission vibrates or lugs when idling. Give it just a little gas and it smooths out. I'm told the idle can't be adjusted. What should I look for? The air filter is clean and I've run a can of Techron thru to no avail. Gas mileage has not changed. Car has 65K miles on it.


First, its a 2.5 engine.

Second, does the problem go away if you put the transmission into manual mode (in other words, if you manually put the shifter into 1) and accelerate?

Third, you can relearn the idle air speed manually with a series of throttle stomps.

Idle Air Volume Learning Procedure
1) Start engine and warm it up to normal operating temperature.
2) Turn ignition switch OFF and wait at least 10 seconds.
3) Confirm the accelerator pedal is fully released, turn ignition switch ON and wait 3 seconds.
4) Fully depress and release the accelerator pedal quickly 5 times within 5 seconds.
5) Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL goes off.
6) Fully release the accelerator pedal within 3 seconds after the MIL goes off.
7) Start engine and let it idle.
8) Wait 20 seconds.
9) Rev up the engine two or three times and make sure that idle speed and ignition timing are within the specifications.

And Fourth, its possible you might have a bit of carbon build up around the throttle plate. Taking off the intake air hose in front of it, and lightly cleaning with a rag and some throttle body cleaner will make it nice and spiffy. You should do that before the Idle Learn Reset procedure.

BC.

 

[bladecutter]

Originally Posted By: ARCOgraphite
Is this the engine that eats the converter core? Or was that an earlier iteration?


That was the previous QR25DE engine, between '02 and '06.
The ones in the '07 and newer cars haven't had reports of convertor failure.

BC.

 

[JTK]

Originally Posted By: Bladecutter
Originally Posted By: ARCOgraphite
Is this the engine that eats the converter core? Or was that an earlier iteration?


That was the previous QR25DE engine, between '02 and '06.
The ones in the '07 and newer cars haven't had reports of convertor failure.

BC.


In regards to torque converter issues, I know way back in the day, our 1993 Nissan Sentra with a Jatco 4spd auto shed it's TC internals at ~63Kmi, so that type of issue could be hit/miss throughout the years. It presented itself by shuddering heavily approaching a stop.

I know the Aisin CVT in my new Soob will advance itself into high range under a no load, low throttle situation, but I gotta say she never lugs, hunts or gets goofy at throttle inputs.

Joel

 

[CBR.worm]

Is this a new symptom? It seems to me that when I rent altima's they do this.

I think the dealer can raise the idle slightly using CONSULT.

 

[MrCritical]

I don't think the idle can be adjusted. Emissions regs. If it can be adjusted, the computer will adjust it right back.

Be sure you are using "Top Tier" fuels. Dirty injectors may affect your idle quality. The dealer can give you a copy of a bulletin on Top Tier fuels.

If you haven't been using Top Tier fuels, it's too late for Techron additive. A fuel injector cleaning may do the trick.

 

[tc1446]

Thanks guys for the good info. Apologies for lateness in responding. Got sidetracked with minor health issue.

I put in new plugs and it didn't change anything.

The vibration goes away when the tran is put in neutral, or you barely press on gas pedal.

Bladecutter provides some good info that I want to try next.
Will advise if it helps. If not, will take it to local mech that has a good rep.

 

[Towncivilian]

Check the fluid level and condition. See page MA-28 of the factory service manual. Alternately, your dealer can plug in their scan tool and the computer will determine whether the fluid will need changing. You will likely be charged a small fee, however.

Also be aware that there is a 10 year/120k mile warranty extension on the CVT. Read here.

 

[barlowc]

To the OP... whatever you do, DO NOT let anyone except a Nissan dealer flush your CVT's AT fluid. (Unless you're absolutely sure they know what they're doing an use genuine Nissan NS-2 fluid.)

During a recent trip to my local Firestone Complete Auto Care for a tire rotation/balance, for kicks I asked about an AT flush for my vehicle. After quoting me $96 and telling me they use a "universal" DEX/MERC fluid, I "educated" them on the absolute need for NS-2 in my CVT and they said, "oh, you have a CVT?"

Towncivilian, thanks for the service manual link! I wish my vehicle had a drain plug on the transmission's pan. It would make a fluid change so easy and not too expensive. Unfortunately I'll have to drain via the cooler line (which I'm not all too comfortable doing myself) and can expect to need 30-50% more fluid which minimizes the cost difference versus having the dealer do it.

 

[asiancivicmaniac]

What about the mounts?

 

[Towncivilian]

@barlowc: ensure you download the 2008 FSM from here (I linked to the 2007 FSM since that's what the OP has): http://www.nicoclub.com/FSM/Altima/2008/
Right click -> save as each PDF into a folder, then use fwd.pdf to navigate.

Nissan actually describes the cooler line exchange method as a method to change the fluid in newer FSMs.

NS-2 fluid is very expensive - $17.27 a quart.

 

[bigmike]

Originally Posted By: tc1446
Thanks guys for the good info. Apologies for lateness in responding. Got sidetracked with minor health issue.

I put in new plugs and it didn't change anything.

The vibration goes away when the tran is put in neutral, or you barely press on gas pedal.

Bladecutter provides some good info that I want to try next.
Will advise if it helps. If not, will take it to local mech that has a good rep.


Hate to tell you this, but most large 4 cylinder engines do this.

Our Accord 2.4 is no different. Purchased brand new, it ran smooth until the ECU "learned" and then it started vibrating at idle. A relearn will smooth it out until it "learns" again. Honda technicians said it was normal, spoke to the service manager and he handed me keys to several cars on the lot - said go try them yourself.

Putting it neutral smooths it out, just like yours. Adding electrical load makes it worse (backup lights, headlights, A/C, defrost, etc). No cure that I know of and it's well known throughout the Honda boards I visit. Can't comment on the Altima forums, though. If you ever figure out a solution, I'd like to try it as well.

 

[barlowc]

Originally Posted By: bigmike
Hate to tell you this, but most large 4 cylinder engines do this.

Unless the OP's description of "vibrates or lugs when idling" is a gross exaggeration, what he describes is not normal, even for a large I4 engine. While the engine in my 2008 Altima Coupe isn't as smooth as the 3.5-liter Honda V6 in our Saturn, I would still describe the Altima's engine as smooth at idle.