Rep Power: 0

Hello everyone, I have a problem that I do not understand. The car is a 2004 Civic 1.6.
The problem is the relay that stays at 500 rpms constantly, does not oscillate and the engine trembles very loudly. So far I have changed so: engine mounts, throttle, Map sensor, O2 sensor, I checked the antifreeze, Temperature sensor, distribution is fine tuned, new battery ... I really do not know what to check ... Any ideas?
Excuse me the way I wrote but I used google translateThe check engine was on because the air filter was removed

 
Rep Power: 125

When did this start?

Your valves may need an adjustment or your engine timing could be slightly off.

 
Rep Power: 0

The car suffered a minor accident on the right side, after which it remained unpaid for 4 months. After the repair started to go wrong

 
Rep Power: 0

I forgot to tell you that I also changed the spark plugs and the coils

 
Rep Power: 125

The accident may have jolted a sensor loose. I'm pretty sure those have a CPS. Check to see if that's still in place and make sure you don't have any other engine codes.

 
Rep Power: 511

Definitely scan to see what codes are being thrown.

In the mean time, you can try and idle relearn procedure: link here
It won't do anything if there are underlying issues.

 
Rep Power: 0

I have no error code, it was scanned 3 times as 2 types of testers. Every time I changed parts that required disconnecting the battery I also made idle relearn but not as it says there that I have to keep the speed at 3000 rpm. I started the car and left it to warm up again until the electric fans started operating. The point is that no improvement was felt after changing the parts, it works exactly as when it first started after the accident. Tomorrow I will try to change CPS and make idle relearn as it says there. Thank you very much for the tips and I hope to come back with good news!

 
Rep Power: 209

As mentioned previously check engine's mechanical (crank, cam) timing and valve clearances.