Rough Idle after running the engine for an hour?

There are a few things that can make it act this way, vacuum leaks, weak MAF sensor, low compression in one cylinder, bad timing chains, please go over this guide to see what the popular problem are, I would try a new MAF sensor because I have seen these sensors cause this problem.

https://www.2carpros.com/articles/repairing-engine-rough-idle-issues

Here is the location of the sensor if you want to swap it out. Also, can you tell me the fuel trims? Please go over this guide to read them:

https://youtu.be/u-4syLc-ifQ

Check out the images (below). Please let us know what happens.

Thank you for your response, Ken. This is the data stream when the engine just starts up.

And in the last 10 seconds of this video. That's where the engine acting up rough.

Hopefully that data helps. Thank you so much Ken.

So what I see is the IAT sensor says it is over 100 degrees, is it this hot where you live? If not, I would replace the IAT sensor first, thanks for the videos they helped. Also, I see a bunch of erratic readings fuel trims, but the IAT might cause this so let's replace that first and clear any codes once competed, here is the location of the sensor which is part of the MAF sensor just to let you know.

We are in a tropical area. But it was impossible to reach that temperature, especially since the engine had just started, and I recorded the video early in the morning. Thank you so much for the help, Ken. I highly appreciate it.

You are welcome, lets swap out that sensor and clear the codes to see what happens.

Dear Mechanics,

The issue is RPMs fluctuations after the car runs for more than 30 minutes.

Engine: 4B11

Things I have done:
1. Cleaned fuel injectors
2. Cleaned throttle body
3. New Fuel pump and filter
4. New Sparkplug
5. New air filter
6. Tried new O2 sensor, but I returned the old one since it's not the issue
7. New Drive belt

Scenario:
I got a check engine light and upon scanning the code is P0132, after removing and cleaning the O2 sensor and the code is gone. While having the code I didn't get the RPM fluctuations.

After a week running the RPM suddenly fluctuates, especially at a stop. After doing the things I mentioned above, still it didn't fix the issue.

Since the sparkplug I bought are pre gap, so I changed the gap. One thing I noticed when I lowered the Gap to 0.7mm, the RPMs fluctuation at a stop is gone but only when running, it's jerking.

Can someone help me identify the issue? I am thinking the ignition coil might be weak, but I don't want to waste money anymore if I am wrong. I need your opinions. Thank you and God bless!

I would make sure you have the correct park plugs at the factory spec gap.

Spark Plug Type:
OEM Recommended Plug: NGK LZFR5BI-11
Alternative: Denso FXE20HR11
Spark Plug Gap:
0.043 inches (1.1 mm)

Let us know how it goes.

My owner's manual says NGK FR6EI, it's the one I bought and tried 1.1mm GAP, the wider the gap, the more the rpm fluctuates. Before it goes 30 minutes, but at a wider gap of only 15 minutes. The sparkplug used before I replaced the new one was NGK BCP6ES.

I forgot to mention that, before I removed the old sparkplugs, it has oils. I am not sure if that's a factor. But, after using a new sparkplug it never happened again.

Yep, that is common to have oil in the spark plug hole. Watching the live stream data, I noticed the MAF sensor all over the map, these can be caused by a bad intake or exhaust valve. Let's try a compression test to make sure we are not chasing our tails.

https://www.2carpros.com/articles/how-to-test-engine-compression

Please go over this guide and get back to us.

Okay, I will order a tool for checking compression. I have 1 question, I found out some oil leaks from the sides of the engine. Can a bad rocker cover gasket can be the cause of RPM fluctuations?

If there is a large enough hole then yes. You can rent a compression gauge at the auto parts store for free FYI. Sorry I didn't say anything earlier.

It's different in our country, everything has a price. Maybe a few will have it for free. Anyway, I noticed that when I ran the car over 100km/h, a burnt smell came from the dashboard. And I checked the engine near the exhaust. There's an oil mark. I think when running that speed the oil escapes.

Did you ever swap out the IAT sensor which was at over 100? and then clear the codes?

No, I have tried on my sister's car. The temperature are the same. By the way I have done the compression test, and it looks good. All Cylinder has the same result 160 PSI.

Yes, the compression look good, were the other cylinders the same? Thanks for the video, it helps. So the basic problem is rough idle correct? I noticed in the second video that the TPS sensor inside the throttle body fluctuates, are you moving the gas pedal at all?