Hello all,

I'm having a problem with my '89 Ford Sierra 2.0i DOHC. I have completely restored this car and it runs good except for 1 thing: when it's warm it has problems with idling, it idles at 1500rpm and then after 5-8 seconds it runs normally again (sometimes it keeps revving high... ).
So the problem is if you're driving it and you're approaching a bend or intersection and have to stop, so you brake and press the clutch and it just keeps spinning at 1500rpm. If you stay standing, it will drop, but that will take a while, about 5-8 seconds or so. It also does this when stationary and you rev it.

The engine warms up nicely and I have already replaced the coolant sensor for the ECU and the one for the gauge in the dashboard, but no difference. It's like it's running on choke but only for e few seconds.

What else happened to it:
- Replace head gasket
- Timing chain, tensioner and guidance rail for de chain.
- All seals engine
- Replace crankcase ventilation tubes
- Idle speed control valve
- Check for air leaks but nothing found
- throttle body cleaned

Anyone else here recognize this? Otherwise it drives perfectly! It's smooth and pulls up very nicely! Or would this be normal for this engine? I've also tried adjusting the idle speed via the adjusting screw, but it practically doesn't respond to it. Also tried using the blink codes.

Here's a video of the problem:
There are still other sensors that might influence this (MAP,Air intake temperature sensor, throttle position sensor, ...) but I don't have these available and are hard to find.

Anyone who could help me with this problem? Or anyone has the same issue with his car?

Thank you in advance!