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[crysisdesign]

Hello dear omega owners!

 I have a problem with the first start of the engine.  on the first start, the engine speed drops very quickly from 2000 to 800 rpm within 7-10 seconds and stands at 864-832 rpm.  Even in cold weather it's still the same.  And one more thing, it twitches when the gas pedal is pressed sharply, and while pressing it, rpm first drops and then it starts to rise.  You can check it out in YouTube link.  After 85 degrees it goes more or less normally, but even then a little twitching is felt.

I changed almost everything, and even the engine rebuilt. As for the sensors, I checked Camshaft , Crankshaft, TPS, fuel pump, IAC, coils, spark plugs and cables, fuel pressure regulator.  Checked almost everything.  But there are 3 possibilities left:

 1. EGR
 2. Temperature sensor for ECU
 3. Automatic box

 1. EGR - there is no hoses attached, the vacuum tube on the throttle isn't plugged, I tried to close the hole with my finger, but same thing happens.

 2. I basically know how to test it, but I can't.  I can’t change it, but the VAUX-COM shows all the temperatures, I don’t know if this could be a problem or not.

 3. The gearbox was replaced with a manual transmission, but the onboard computer shows an Automatic Gearbox error.  Even the gearbox ECU was not plugged out, so I unplugged it myself so I can check if something changes, but nothing. I'm stuck with this problem and can't solve, so I need your advice

Have a nice day everyone!

https://youtu.be/gDTVQP2ncng (check light isn't on anymore, but the problem persists.)

[crysisdesign]

BTW car is 97 model pre facelift X20XEV engine.

[LC0112G]

My bets would be either the coolant temperature sensor, or the idle air control valve.

Does your code scanner show live data? if it does, then first look at the engine coolant temp sensor value - does it look sensible? Starting from 20C ish when cold, rising to 85-90C when warm?

Don't know what sort of IACV is on the 2L, but a good clean with carb cleaner shouldn't hurt it. It may also be possible to watch the IACV duty cycle on the code scanner. Sometimes you can even control the IACV to set the idle speed during diagnosis.

[crysisdesign]

I fixed the first start issue, but twitching and other hesitations are still issue. first start issue was the problem with automatic gearbox, car swapped with manual transmission, but ECU still showed the automatic transmission, after I bridged 4th pin to ground the issue fixed. but other issues still persists.