UPDATE: FIXED! DIRECTLY BELOW IS THE THINGS I TRIED AND WHAT SEEMS TO HAVE FIXED THE IDLE. I'M ITALICIZING MY ORIGINAL POST SO THAT IF SOMEONE WANTS TO THEY CAN READ THROUGH THE THREAD IF NECESSARY.

SYMPTOM - rough idle in drive but not in park
CAUSE - seemed to be bad spark plug(s)
REMEDY - new PFR5G-11 NGK plugs (all 6)

Steps tried to fix:

• SeaFoam
• Clean TB
• Clean IACV
• Check for vacuum leaks
• Test IACV, TPS, and ignition coils with Multimeter
• Replace spark plugs

I'm at 281k right now.


I have already replaced the IACV, plugs, plug wires, (recently), and done the normal maintenance always, etc.

She purrs like a kitten most of the time, but the last 1000 miles for some reason the idle WHILE IN DRIVE sits around 480-500 rpms. It stutters a tiny bit at idle as well. I can rev it with the brake on to around 650-700 rpms and the stuttering goes away.

When I stop and put it in park the idle jumps back up to 700.

I've adjusted the idle per the FSM more times than I can count at this point.

Any ideas? I really want to keep her for another 2 years and see her reach 300k and beyond.

this is a joke right it idles between 4800 and 5000 rpm's ??? sounds crazy to me, burning a little oil are we ??

maybe you mean 480 and 500

idle that high???? never have rhd of that before. U check accelerator cable?? TPS??

crap...I hadn't had coffee yet...fixed.

When was the last time you checked the condition of/cleaned the throttle body?

even so my car idles at 500 - 600 and runs fine???

About a year ago. I'm going to clean up everything again tonight just to be sure...but wanted to see if anyone else had a solution.

Have you checked the injectors with a multimeter?

you might have one starting to go.

No...do you have any instructions? Is it in the FSM?

Maybe the fuel pressure regulator?

What's odd (at least to me) is that if I put it back in park then it works just fine. It's only in Drive while sitting at a light that the idle is rough.

Clean your TB and see if that helps.

Clean TB, check the TPS, also if you ever manually read codes check the screw on the ecu its possible that its not in the right position

idle? air? have u checked IACV?

its in the FSM but pretty much all you do is take an ohm meter and unplug the injectors and test them...they should be about 10-12 ohms

If your getting no misfire codes and the rpm only rattles while idling then you could be getting detonation. I had that problem for about 2 years but I fixed it after cleaning up the carbon in the combustion chambers.

An easy way to clean the combustion chambers is to have a cleaning fluid or spray sucked via the brake booster line. A more thorough way of cleaning those chambers is to spray carbon cleaner down in the spark plug wells. Reconnect the negative battery cable but leave the coils and plugs disconnected. Turn the engine over 2 to 3 times so the injectors mix gas with the carbon cleaner. After letting it sit for a few hours clean the wells with lint-free rags then reconnnect the coils and plugs. Get ready for a an exhaust cloud when you start her up.

It kinda sounds to me like his torque converter's too tight. Any way that can happen?

or he could do the easiest thing first.

Start by checking the injectors, then clean the throttle body and report back

I'm gonna try the seafoam thing tonight and report back.

Thanks all.

I have the same dam problem for the past 3 months..

it would flucuate between 500-600 really quick on in D.... it would not always happen....I would then just rev it and its back to normal...

UPDATE:

So I cleaned out my throttle body completely. Took the whole thing off (what a pain...it's never been off before it seems and the hoses didn't want to pry loose).

Much better than it was, however still hesitates a little.

I'm going to Seafoam it tomorrow and report back again. Here's to my car reaching 300k...

My problem started after I changed the rear valve cover. So i am guessing it has something to do with intake/MAF.
I have an idea:
Being that the rough idle only happens in drive (lower RPM)
Can we say if you hit the AC button when it happens, we can raise the RPM while still in drive.(Higher RPM)...this should tell you weather its and intake problem or something bigger like torgue converter???

Jus get some MAF cleaner and spray MAF generously.

Personally i dont like SEAFOAM. If you dont do it right you can mess up your car...And if u actually do it right u still get plumes of smoke out your tailpipe.

Try Chevron Techron. Works wonders for me man, If u read the product descrpition on the back of the bottle, it ABSOLUTELY does what it claims. Better MPG, Serious cleaning, better performance. Great stuff

Everything is cleaned out and the problem persists.

I've been reading that the following could be suspect:

TPS sensor
IACV
EGR valve
spark plugs (which I replaced last year)

So, any suggestions now? Should I go with that list and if so, which should I replace first?

I would say IACV. If u havent cleaned it then try that. Then move onto TPS. Check coils too

Cleaned the IACV tonight and replaced both the TB and IACV gaskets as well.

Can't tell from a brief drive what it affected yet.

Something that always gets me though:

In drive at idle holding the brake the engine idles around 550.

Drop it to park and it shoots up to 900.

This always happens...regardless of what I do. That's gotta indicate something I would think.

I'm not trying to be mean, but there is this thing called common sense. Perhaps you guys have heard of it, I hear it is the new "thing" this season!

But yeah, its pretty obvious he accidentally put in a extra zero, so can't we just get to the main point of answering this man's question without pointing out the obvious?

Ok thats cool. If u have cleaned MAF and IACV, and TB, see how car responds. U may have to replace TPS. But TEST it first per FSM using a multimeter. Its easy to test. U still need to test IACV per FSM even if u cleaned it.

Another question in relation to this:

When I was putting back on the TB I noticed there is a screw and nut that you can adjust that seems to change the closed position maybe on the TB?

It's on this pic in the lower left hand of the pic attached to that big spring:



It has 2 lines on it and then another line on the part where the cables for the throttle connect. Sorry, but you can't actually see it in this pic, as it is on the backside.

Should those line up or something? Mine doesn't at all...so I was curious.

As far as the throttle body pic, you shouldn't adjust any screws if the idle was fine previously seeing that you have an Auto. What you should do is try doing the TCM diagnostic and see if it throws you back any codes. I was curious to look up how to do it and found that I had a code for the TPS but the check engine light was never lit. I do have hard shifts from 1st to 2nd gear but it goes to show that the check engine light will not come up for everything.

I've noticed that after I used SeaFoam, both of my Maximas engine's got louder in regards to lifter-like ticking... Both the VG30e with 195k miles and my VQ30DE with 329k

btw, you're at about the mileage that my Maxima had when I bought it, it had 286k in June 2008.

Keep it up and you'll be at 300k+ in no time

Are your plugs NGKs?

I don't remember what I replaced them with. I think they were Bosch because I remember seeing the NGK's at Autozone and going " I'm not paying that."

I haven't replaced the plug wires.

I think I'm going to be checking the plugs again tonight though just to see if any of them look bad already, but I would think I would get either a CEL or some hesistation overall and not just at idle.

I have the same problem you have, except it does not return to normal idle when in neutral (I have to really rev the engine to make it idle normal), plus it doesn't happen all the time. Seems to happen more frequently when it has run for a while. Please post the solution if you ever fiugure it out

You should ensure that the plugs are NGK. You can get the copper ones if you don't want to pay for the platinum ones. I seem to remember something about Bosch plugs not working well in the VQ30

Yeah he has a point there. I posted that same comment for someone else in another thread about using NGK. Yeah they are pricey because I have the NGK Iridiums from AutoZone and paid $45 for all 6 but look at it this way, another 100,000 before another change versus copper which I am pretty sure you will be changing sooner and cost you more than what I spent.

It's also very rough starting it...I have to rev it sometimes to keep it from dying.

I checked the TPS tonight and can't really figure out if it is bad or not. Resistance is around .400 at idle and just shoots up to 1. if I floor the pedal (with the car off obviously).

I'm probably checking it wrong, even though I'm following this link: http://vbxmaxima.8m.com/tps.html

I'm thinking about replacing the TPS and the plugs again and just see what happens before I take it in to someone.

Are you saying the copper plugs cost more? They are about four dollars a piece compaired to the platinums at around ten. The iridiums are about eight.

Thread about sparks plugs in the VQ30.

OP, before you take you car in for service, try the NGK copper plugs.

I will.

According to NGK's site though any of the following plugs will work:

Spark Plug Part No. Stock No. Plug Gap
Standard BKR5ES-11 2382 .044
V-Power BKR5E-11 6953 .044
G-Power BKR5EGP 7090 .044
Laser Platinum PFR5G-11 * # 2647 .044
OE Laser Iridium IFR5E11 ^ 7994 .044
Iridium IX BKR5EIX-11 5464 .044

With the PFR5G-11 being the OEM plug.


I can get the G-Power for $2.59/each, while the Laser Platinum OEM's are $10/each. Both are platinum plugs. It appears from others on the forum that the G-Power plug will work fine just needs to be changed sooner. Agree?

I think most use the IFR5E11 (OE) or the BKR5E-11 (V power). I have the IFR5E11 and they work fine, but from what I've read, copper plugs have a lower resistance, meaning a stronger spark, but the trade off is that copper is softer than platinum, meaning they don't last as long. I would think any plug from that list would work, as NGK says they are all interchangeable. Personally, I would stick with the IFR5E11 or the BKR5E-11.