Strange idle this morning

[J30inthe sun]

This morning I started my J, it started & idled normal. I drove about 1 1/2 miles, stopped to get coffee. When I started it back up the idle went from @1500 rpms to @100-200. this happened about 5 times within about 15 - 20 seconds before the idle when so low that it stalled. I tried to resart it 3 - 4 times & the same thing happened. I waited about 2 minutes & tried it again, this time the idle stayed @1200 rpms in park without any ac & the engine was fully warm. I started driving, drove about 3 miles & as I turned into a street is stalled again. When trying to resart the same thing happened earlier, idle went from @1500 rpms to @100-200 several times & stalled. I waited about 2 minutues & restarted this time everything was fine. I drove about 5 more miles to work, hitting several stop lights & everything was normal with the idle at stop lights.

Recent work done & parts repaced over the last 6 months & 4,000 miles:

Air filterFuel filterCleaned MAFIdle air control valve cleanedNew Throttle position sensorNew OEM NGK spark plugsTiming belt kit2 bottles of Redline fuel system cleaner

The CEL is not on. Anyone have any thoughts? i have never had this happen before.
Modified by J30inthe sun at 5:37 PM 3/12/2009

[Infinitiguy19]

Check the connector and board on the MAF sensor.

[J30inthe sun]

Check the connector and board on the MAF sensor.

How do I check the board & what do I look for?

[SteveTheTech]

That sounds like an AAC valve issue. If the idle speed cannot be controlled due to dislodged carbon in the linear solenoid assembly you idle will tend to be erratic. Click Here for the J ESM and refer to the EC section that will describe the process to remove the valve. Once you get it out use some throttle cleaner on the inside of the chamber. I have seen many people clean throttle plates and the the sludge can collect inhibiting operation.

Try cleaning it up.

My Js idle increases to 1450 when I park in 1 spot at my local 711. This spot is on a pretty steep right incline. IDK what it is and it doesn't pose enough of a problem ATM to deal with.

[J30inthe sun]

I just had it cleaned last November, maybe they did not do a good job.

After work it started & ran normal, I drove around for about half an hour with various starts & stops. Another short trip several hours later & still everything is fine. Hopefully it was just a one off problem.

[Infinitiguy19]

Peel the black square piece off the top of the MAF sensor.

[J30inthe sun]

That sounds like an AAC valve issue. If the idle speed cannot be controlled due to dislodged carbon in the linear solenoid assembly you idle will tend to be erratic.

My shop installed a brand new IACV from Infiniti, I saw it 1st hand, brand new in the Infiniti parts box with a new gasket.

After IACV replacement, the TPS was set at 0.52V & the IACV was set to FSM specs for idle RPMs with the car fully warm w/ TPS disconnected. FSM manual instructions were then followed to "RESET IDLE POSITION MEMORY" (page EC-74)

Unfortunately I still have the same problem. The car will be idling fine in drive with foot on brake & then suddenly stall. If I see it happening I can put it in neutral & feather the throttle to catch the rpms from dying. Then rev the engine to 2000 rpms for about 30 seconds & then the problem is gone. At 2000 rpms the engine is running nice & smooth as normal.

Things replaced/fixed last 7 months (108,000 - 114,000 miles) that could affect idle:

Full timing belt kit w/ all belts & idlers (7 months ago)New OEM NGK Spark plugs (6 months ago)New OEM Throttle position sensor (7 months ago)New OEM IACV (last Friday)New battery (last Friday)Cleaned MAF (last week & 5 months ago)New air filter (2 weeks ago)New fuel filter

I have been using Shell 93 octane gas for about 5 years now EXCLUSIVELY. About every 3 months I use a fuel system cleaner & have been doing that since I have owned the car from 39,000 - 114,000 miles. The last 4 bottles of cleaner have been Redline S1.

Anyone have any suggestions?
Modified by J30inthe sun at 8:46 PM 4/12/2009

[Infinitiguy19]

What about the circuit board on the MAF is it free of bad solder joints and burning?

Basically open up the MAF and check if its the original one.

[J30inthe sun]

I am really concerned that I might mess it up by trying that or that I will not know what to look for. Can't I test it?

[Infinitiguy19]

There is way to test it in the FSM which requires a Consult (Real or Laptop version) or you can splice something together with a VOM. But sometime you can get false results.

But the truest way to test is a visual inspection of the board.

[driverdriver]

Is your engine getting enough fuel? It could be that your fuel pump/sending unit is slowly starting to fail. You may need more time to properly diagnose.

If it's a one time occurence, could be bad gas or a badly blended mix of gas. That sometimes happens up here especially in the fall or spring.

[J30inthe sun]

Is your engine getting enough fuel? It could be that your fuel pump/sending unit is slowly starting to fail. You may need more time to properly diagnose.

If it's a one time occurence, could be bad gas or a badly blended mix of gas. That sometimes happens up here especially in the fall or spring.

The car will be idling fine in drive with foot on brake & then suddenly stall. If I see the RPM dropping I can put it in neutral & feather the throttle to catch the rpms from dying. Then rev the engine to 2000 to 3000 rpms for about 30 seconds & then the problem is gone.

At 2000 to 3000 rpms the engine is running nice & smooth as normal which would lead me to believe it is not a fuel starvation problem.

Every time it has stalled I am able to start it right back up.

I drove to work this morning @ 8 miles that included 1 stop for coffe after about 2 miles & the car drove perfect.
Modified by J30inthe sun at 9:08 AM 4/13/2009

[J30inthe sun]

There is way to test it in the FSM which requires a Consult (Real or Laptop version) or you can splice something together with a VOM. But sometime you can get false results.

But the truest way to test is a visual inspection of the board.

I can't afford to open it up & mess it up & be stranded.

Unfortunately I am going to bring it to the "Stealership" in the morning. I'll bet its going to be a quote of $500 - $1000 for "whatever" they find wrong. I really dislike the local dealership here I think they are very dishonest but I need to get this fixed once & for all. Will keep you posted.

After sinking @ 5-6 g's into this over the last 7 months I can't afford not to. I am planning on driving this for another 2 years, I have no payment, the car still looks great inside & out & drives great, when it doen't stall. Oh & I have no payments! Oh & they will give me a brand new loaner for they day

I am promising myself to leave my check book at home.

[J30inthe sun]

Peel the black square piece off the top of the MAF sensor.

If I peel it back will I be able to put the black square back if it all looks OK?

Should I use a tool?

I didn't have time to go to the dealership today.

[J30inthe sun]

...the truest way to test is a visual inspection of the board.

I opened it up & everything looked brand new inside, nothing burnt looking at all, no broken looking solder connections. I didn't unsrew the top board to look at the bottom board however.

The connector looked all ok as well.

I replaced the MAF anyway with remanufactured Cardone brand one from Autozone for $215 plus tax. It seems like the idle is already better. Time will tell.

I will post back with an update in the future.

[J30inthe sun]

Check the connector and board on the MAF sensor.

Replacing the MAF with a remanufactured Candone unit seems to have done the trick! It has been 3 days so far & no problemos. If it was not fixed the condition would have recurred already about 5-6 times already.

Thank you PaulWall!

What made you believe this was the cuprit?
Modified by J30inthe sun at 6:32 PM 4/16/2009

[joeysj30]

Is your car still runnig good? I have the same problem with my j30 and I dont have a lot of money to thro away! When I had the codes read it said it was the EGR valve code and so I replaced that. But I dont wanna replace anything else if I dont have to.

[J30inthe sun]

It ran perfect this morning again on my 15 minute 8 mile drive through city traffic to work this morning.

[J30inthe sun]

Is your car still runnig good? I have the same problem with my j30 and I dont have a lot of money to thro away! When I had the codes read it said it was the EGR valve code and so I replaced that. But I dont wanna replace anything else if I dont have to.

Welcome to NICO!

Several days now & the car is running & idling perfect. I am halfway through a full tank of gas with Redline S1 in it. Couldn't be happier based on my experience over the month.