u/Imaginary-Ice-6950

I’ve had my 90 Series Prado (3RZ-FE) for about a year now. Around six months ago, I started having idle issues. After driving for about an hour, the idle speed would occasionally drop to around 200 rpm. It only happened at idle.

At the time, I cleaned the idle control valve, and that seemed to fix the problem. The car ran perfectly for about five months.

However, over the past month, the issue has returned. At first it only happened occasionally, but now it happens every time the engine is idling. The idle sits at around 500 RPM, and cold starts are only around 700 RPM (it used to idle at about 1,100 RPM on startup before this problem).

The idle is also unstable. If I rev the engine, the RPM drops to around 200 RPM, the whole engine shakes quite badly for 2–3 seconds, and then the RPM slowly climbs back to around 500 RPM, where it stays.

Last Sunday, my friend took me for a spin in this E30. I never had time to ask him about the specs of the car, but I’m pretty sure it has an engine from an E36 3 Series. Now I wanted to ask if anybody knows which engine it is. Is it the M50B25 or something else? Thanks.