Renault Laguna I 1.8 16v: Warm Engine RPM Hang Issue, Gasket Replacement, Damper & Throttle Repairs

Hello,

I have had a problem with freezing rotation in my Lagoon for a long time. The problem mainly occurs when the engine is warm, but this is not necessarily the case. When disengaged, they should drop to 750-800, and stay on the same as before the gear change. It does not happen all the time - yesterday I made a 200 km route and this phenomenon appears once for a dozen or so km, disappears and then reappears.

From the mechanical side, I changed all the manifold gaskets and both on the throttle to new originals from ASO.
Damper thoroughly cleaned. Checked how it works mechanically and there are no jams.
Stepper motor also replaced. This time a replacement, but not the cheapest
Throttle line free, armor is smooth and undamaged.
I patted the inlet and the pipes next to the stepper with a poster, but there is no spin reaction.
The mechanic's computer does not see any errors. The lights in the car are also off.

I played a bit with the diagnostic connector and bought a reader for OBD2 ELM327.
At idle, the indications are 9 - 9.4% opening. I guess it's a normal value, but no one confirmed it.
I've only seen similar in others. At the moment of this suspension, these indications also amount to 9% and the revolutions are much above idle.
During the last tour, we managed to bring the RPM to the point where the speed was practically under the limit after pressing the clutch.
It happened after I was driving on the air conditioning for some time. After turning it off, they didn't go up like that anymore, but kept hanging.

I also monitored the temperature readings with this reader. On the board it shows perfectly in the middle of the scale.
On the other hand, the computer reads the liquid temperature around 81-83 degrees during normal driving.
I didn't manage to do more while driving. At idle, the readings slowly go up to 99 and the fan turns on.

I do not know what to do next because it is irritating and worse, it certainly does not have a good effect on the car.
Give me a hint, because I am a bit uncomfortable to list all the suspects I have read about - TPS, mapsensor, temperature sensor, and maybe one more time.

EDIT
Engine F4P 760 1.8 16v 120 HP year 1999

EDIT2
I am asking for tips on what else to check and how.

Clip buddy Not some inventions and give a screenshot of the parameters on a cold and hot motorbike. Like the compression pressure on a cold and hot bike.

Just in case - what is the battery charging voltage? I know cases where the increased charging voltage caused the just described "hanging" as if the gas line was temporarily rubbed in the armor.

I have a similar case which is in megane ii 1.4 gasoline. After heating and touching the gas, for example, 2 thousand revolutions, it drops to 900 and after a while it raises itself to, for example, 2 thousand and it stays like that. Honestly, everything was replaced along with the fuel in the tank and I could only think of hanging the valves on one cylinder because there are different pressure surges on this cylinder. Once 8 and in a moment 12. I think that when the valve freezes, the car sees a leak and raises the speed itself.

Thank you for your interest in the topic ;)

As for Clip, unfortunately I don't have it. The mechanics in my area also not very much. Errors will delete, but if I wanted something more, it's bad.
I can visit an authorized service station - I have 17 km to it and they will do me a service for PLN 150. But I will not be able to read on the cold.

When I feel that the revs have slacked, there is no engine braking (I'm going in gear as if I had a cruise control) but I can lower them, for example, when reaching the lights on the gear and when they go down to 1k, they do not raise themselves. Loading the engine, e.g. with air conditioning or heating the window, makes it much easier to suspend the revolutions. After turning them on, the revs drop much slower than without.

I know the previous owner was making the warhead. He told me about it when I bought it and showed me the receipts.
I changed the oil and filters and made it 10k km from purchase. There was practically no oil or coolant wear, which would indicate a bad repair.

I wonder when he did that head

The version was such that after buying the car, he changed the timing as standard and the belt felt thin.
He wasn't quite going but he did some damage.

Hello,

did you manage to solve this problem? I have the same with Renault Thalia 2003 (1.4 8v LPG)

This is how I managed to fix the problem.
All these mechanical matters that I described in the first post are important but the main reason was the throttle position sensor error.
And basically, these are two errors because the abs sensor in the right front wheel, but I'm not sure if this had any additional impact (the speed is read by the ecu from the abs sensors just)
Replacing both of these did the trick. I bought the throttle sensor in an automotive store - it was not cheap because it was 130 zlotys. I know a drug in good condition would be a better option but I couldn't find it.