Recent Topics
Solar lights that last all night
by Snagglefoot. 12/16/18 09:20 AM
Things Santa might say......
by ZZman. 12/16/18 08:24 AM
ULTRA-POWER 57082
by ET16. 12/16/18 06:56 AM
No collision totaled vehicle
by madRiver. 12/16/18 06:32 AM
Brightest backup light for my daughters car?
by BobsArmory. 12/16/18 06:26 AM
M1 0W20 EP Good To At Least 10K Miles ?
by ChrisD46. 12/16/18 03:29 AM
Gift for young Army Cadet
by Snagglefoot. 12/16/18 12:33 AM
Instacart Grocery Delivery
by dogememe. 12/16/18 12:26 AM
My brother bought this...
by miden851. 12/15/18 09:12 PM
Watch out for scammers
by Chris142. 12/15/18 08:45 PM
15K OCI R53 2006 Mini Cooper S 144k
by dx92beater. 12/15/18 08:32 PM
Beneficial clean fuel.injectors in Ultrasonic Cleaner
by JLawrence08648. 12/15/18 06:54 PM
Back to Basics III
by MolaKule. 12/15/18 05:30 PM
Newest Members
MikeMTL, AJ11, bandito, Spkrdctr, torchredone12
66691 Registered Users
Who's Online Now
103 registered members (53' Stude, 69Torino, 1foxracing, 4WD, 2003f7, 9 invisible), 1,916 guests, and 40 spiders.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums67
Topics295,143
Posts4,928,502
Members66,691
Most Online2,553
Oct 27th, 2018
Donate to BITOG
Previous Thread
Next Thread
Print Thread
Hop To
Idle randomly dipping #4498704
08/26/17 12:31 PM
08/26/17 12:31 PM
Joined: Apr 2013
Posts: 2,423
The Northeast
mclasser Offline OP
mclasser  Offline OP
Joined: Apr 2013
Posts: 2,423
The Northeast
This is in my Pilot.

90% of the time, the car idles at a solid 750 RPM at a traffic light with all accessories off. But the other 10%, the idle dips to like 600-650. When this happens, the engine makes a rumbling noise and you can feel the center console shake a little. BUT...turn on the headlights or A/C, the idle rises and everything smooths out again. It's strange that this happens intermittently. Car drives great otherwise.

Any ideas what could be going on?


2018 Hyundai Elantra VE -- 6K
2013 Honda Pilot EX-L 4WD -- 57K
2002 Honda Accord EX-L -- 212K

Re: Idle randomly dipping [Re: mclasser] #4498794
08/26/17 02:57 PM
08/26/17 02:57 PM
Joined: Sep 2016
Posts: 1,418
Minnesota
bioburner Offline
bioburner  Offline
Joined: Sep 2016
Posts: 1,418
Minnesota
Maybe the 5 year old battery is starting to fail and the alternator is having to engage more to keep the system at 13 or so volts.
Many cars the AC system still exercises to keep seals good even with the switches off.



97 Ford E350 D,99 F350 dually D
13 Scion Xb
12 Ford Transit Connect
06 Nissan Xterra
03 K1200 BMW
07 Kawasaki KLR650
13 Madass
Re: Idle randomly dipping [Re: bioburner] #4498800
08/26/17 03:06 PM
08/26/17 03:06 PM
Joined: Apr 2013
Posts: 2,423
The Northeast
mclasser Offline OP
mclasser  Offline OP
Joined: Apr 2013
Posts: 2,423
The Northeast
Battery was replaced earlier this year; connections are all clean & tight.

In addition:

- All fluids are clean & full.
- I mainly use BJ's gas but fill up at Top Tier stations every 3rd tank or so to keep things clean.
- Inspected the air filter. It's 25k miles old but light still shines through; manual says to change every 30k.

I'm thinking about cleaning the MAF sensor & TB. I don't expect them to be dirty at only 45k miles but maybe it'll make a difference.


2018 Hyundai Elantra VE -- 6K
2013 Honda Pilot EX-L 4WD -- 57K
2002 Honda Accord EX-L -- 212K

Re: Idle randomly dipping [Re: mclasser] #4498840
08/26/17 04:19 PM
08/26/17 04:19 PM
Joined: Jan 2009
Posts: 6,521
New England
gathermewool Offline
gathermewool  Offline
Joined: Jan 2009
Posts: 6,521
New England
My Civic will idle rough (haven't heckled RPM) after being fully warmed up and at higher ambient temps. This seems to coincide with the ELD sensing low electrical load and lowering supply voltage to 12.6 or so.

Turning even just the running lights on (all but headlights on) will raise the voltage to normal. The vibration doesn't go away completely (likely something else is the root cause of that) but the the vibrations do lessen.


'14 Forester XT FA20DIT (Cobb Stage 1)
Edge 0W-40 + FU filter (64,774 miles)
'15 Legacy FB25 (OEM Stage, uh, neg. 7?)
Edge 0W-20 + FU filter (40,803 miles)
Re: Idle randomly dipping [Re: mclasser] #4498855
08/26/17 04:39 PM
08/26/17 04:39 PM
Joined: Dec 2006
Posts: 978
midwest
JamesBond Offline
JamesBond  Offline
Joined: Dec 2006
Posts: 978
midwest
Maybe it's the cooling fans or ac kicking on. Try cleaning the throttle body.

Re: Idle randomly dipping [Re: mclasser] #4498965
08/26/17 07:49 PM
08/26/17 07:49 PM
Joined: Apr 2016
Posts: 968
KS
FordBroncoVWJeta Offline
FordBroncoVWJeta  Offline
Joined: Apr 2016
Posts: 968
KS
Might be time for a new intake sensor.


2017 Volkswagen Jetta 1.4T - 2015 Honda CRV 2.4 - 2012 Volkswagen Jetta 2.0 - 2001 Pontiac Sunfire 2.2
Re: Idle randomly dipping [Re: mclasser] #4498990
08/26/17 08:33 PM
08/26/17 08:33 PM
Joined: Jan 2017
Posts: 336
Texas,USA
ATex7239 Offline
ATex7239  Offline
Joined: Jan 2017
Posts: 336
Texas,USA
Go get the battery, alternator, voltage reg, etc. checked anyways. Sometimes you get a bad battery. Autozone with do it for free.

I've had bad or fouling plugs give me a rough idle, as well. Might be good idea to check those out and test the coil packs.


'12 Buick Enclave 150,xxx
Valvoline ML SynBlend 5w30
ACDelco PF63E

'17 Ford Fusion (Company Lease) 54,xxx
Oil � Don't know
Filter � Don't care
Re: Idle randomly dipping [Re: mclasser] #4501727
08/29/17 07:42 PM
08/29/17 07:42 PM
Joined: Jan 2010
Posts: 954
North Carolina
4ever4d Offline
4ever4d  Offline
Joined: Jan 2010
Posts: 954
North Carolina
Check the IAC valve. They will get dirty and cause idle issues. Throttle body cleaning will sometimes cause this problem also.


04 Chevy Colorado 3.5 I5 5w-30 OEF
07 Honda Element 2.4 I4 5w-20 OEM
10 Nissan Rogue AWD 2.5 I4 5w-30 OEF
Amsoil Products & Fram or Wix Filters





BOB IS THE OIL GUY® Powered by UBB.threads™