Engine low idle?

Tiny
FERNANDO D. RAIMUNDO
  • MEMBER
  • 2012 DODGE JOURNEY
  • 2.4L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 64,000 MILES
I bought the vehicle listed above last month. When in idle, in park, neutral, reverse or drive, I noticed the RPM dropping. Never a problem while actually driving. Nothing worrying, but it bothers me. So, I took out my tools, removed the air filter (which is new), got to the IAC and was happy to see some carbon build up, because it meant I found the culprit. Cleaned it with some WD-40 real good and put it back together. Just to be on the safe side, I changed the spark plugs for some new Mopar NGK. Started it, left it for 45 minutes and it ran perfectly. Not a stutter. Two weeks later it started to drop the RPM back again. At one point the vehicle was in neutral, and it actually shut off. Put it in park and started right back up.
About an hour ago I took it all apart again and cleaned it again the same way. Only this time I found some brownish oil in the bottom of the intake after the IAC. As I'm writing this, I'm thinking maybe some of the WD-40 I used to clean last time got in some crease and while I drove, it mixed with the new carbon buildup and ended up washing down to the bottom. Took out the PCV valve, shook it and it clicked. Blew air with my mouth form one side and it passed. Flipped it and air doesn't go through. So, I think it's fine.
I'm seeking your wisdom to find out what's causing this issue. I'll read all your theories. Thanks
Saturday, April 22nd, 2023 AT 9:24 AM

9 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
Hi,

If you are seeing a small amount of oil in the intake, don't be alarmed. The PCV also allows oil vapors to be drawn into the system which can cause this.

As far as the idle issue, are you certain there are no engine vacuum leaks? Additionally, is the airway where the IAC connects clear? Is the IAC new? Are there any diagnostic trouble codes stored? If the engine stalled, I would think something should be stored.

Let me know. Also, here is a link that explains how to locate a vacuum leak. Take a look through it and see if it helps.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Also, let me know if you cleaned the throttle body.

Take care,

Joe
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Saturday, April 22nd, 2023 AT 8:56 PM
Tiny
FERNANDO D. RAIMUNDO
  • MEMBER
  • 5 POSTS
Hi,

I'm sorry for my ignorance. I thought the IAC and the throttle body were the same thing. It was the throttle body which I took out and cleaned it with WD40. The vacuum leaks make sense, but shouldn't it be always the same? Because it seems to be getting worse. I will try to have the vehicle scanned this week and let you know what they tell me.
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Sunday, April 23rd, 2023 AT 9:05 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
Hi,

No problem. I never heard of using WD40 for cleaning the throttle body. Normally, I use carb cleaner. LOL

As far as the codes are concerned, I think they will help. If you look below, I attached an example. Note that it indicates possible issues to check.

Let me know what you find.

Joe

See pic below.
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Sunday, April 23rd, 2023 AT 6:55 PM
Tiny
FERNANDO D. RAIMUNDO
  • MEMBER
  • 5 POSTS
Hi!
So, I just had it scanned, there were a couple of codes. Mostly about valve timing, if I'm not mistaken. He cleared the codes, but the engine kept doing the stutter. The mechanic said it's probably time for the timing chain to be replaced. I think on this engine it should be changed at 60,000 miles, and I'm just over that. What made us curious was that the engine light doesn't turn on when I turn on the vehicle. I've never seen it light up. He thinks maybe it burned or the guy who sold it to me covered it with some tape.
He also told me to check and clean the sensor in the picture.
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Monday, April 24th, 2023 AT 2:55 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,269 POSTS
Hi,

This engine has a timing chain, so it should last the life of the engine unless we have a tensioner issue or other failure. It shouldn't need to be replaced at this mileage.

Now, the idea there were valve timing codes is interesting. The engine has variable valve timing. The Variable Valve Timing (VVT) assemblies are actuated with engine oil pressure. The oil flow to the VVT assemblies is controlled by two Oil Control Valves (OCV). There is an OCV and Camshaft Position Sensor (CMP) for each camshaft.

If there is an issue with a sensor, actuator, or the oil is extremely dirty or hasn't been changed on a regular basis, it can be the issue.

I need to know the codes he found. And certainly, hold off on the timing chain unless there is excessive noise from it, or you know of a problem.

Let me know.

Joe
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Monday, April 24th, 2023 AT 6:58 PM
Tiny
FERNANDO D. RAIMUNDO
  • MEMBER
  • 5 POSTS
Alright, so.
I did a trip. 110 miles to my brother's house. All good, except for the idle issue. When heading home, did about 20 miles and all was good. I had the music on, so I didn't hear till I passed a semi and in the pause between songs, heard the engine doing a constant 'rrrrrrrrrrrrrrrrrrrr.'
I want losing speed or anything, just the 'rrrrrrrrrr'.
I stayed at 50-60 mph. I didn't want to pull over, because if I had to shut the engine off, I didn't know if it would start up again. And in the middle of the night, in a dark road, in the country, I didn't want to risk it.
About 80 miles later, I made it to the highway where at least I had light posts. As soon as I merge in, noise got worse, and oil light came on.
Pulled over, shut it off, and check on the trunk where I knew I had an oil bottle the previous owner left there.
Only about 250 ML of 5w40 (I think about 9 Oz)
Started again, and drove at a constant 45mph till I made it home, about 10 miles away.
Engine shut off in the traffic light in my block, started again, made it inside the garage and has been off since because I've been away since Monday morning.

Checked oil level this morning and it's where it should be. And a friend let me borrow an OBD-2 scanner and got the following.
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Friday, May 12th, 2023 AT 9:10 AM
Tiny
JACOBANDNICKOLAS
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Hi,

I wouldn't have pulled over either. LOL I looked at the codes. There are a lot of them. However, the first one I need you to check is the P0118, coolant temp sensor. If that is off, it can cause havoc. The idea that you have the cam/crank sensor codes is a bit difficult for me to accept with the mileage on the vehicle. However, it is possible.

So, if the scan tool you have has live data, connect it. Check to see what the coolant temperature signal indicates. It should be close to the ambient temperature outside before starting it.

Let me know.

Joe
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Friday, May 12th, 2023 AT 7:25 PM
Tiny
FERNANDO D. RAIMUNDO
  • MEMBER
  • 5 POSTS
I'll check it tomorrow, and hopefully send you a video. So far, in the month and a half since I've owned it, it never overheated. And I was in heavy bumper to bumper traffic for about 2 hours last Friday night.
Things I find odd, is that engine light has never come on. Not even when starting the car or having it on accessories or the run position. It's almost like the light is either burned or the previous owner covered with something.
Also, I live in Argentina, and it's not against the law to modify the odometer. I know, third world stuff, you don't have to tell me. But I'm starting to think maybe the previous owner lied or withheld some stuff. I found it peculiar that he would carry a bottle of oil in the back.
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Friday, May 12th, 2023 AT 7:56 PM
Tiny
JACOBANDNICKOLAS
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Hi,

Thanks for the update. Let me know what you find.

Take care,

Joe
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Saturday, May 13th, 2023 AT 10:07 PM

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