Stalling idle is finally fixed.
I did exchange the spark plugs and all the cables and boots. Didnīt help. Then exchanged the OVP, this helped with the idle problem while cornering. At least so I thought. The stalling and rough vroom vroom idle when cornering in my case was caused by one of the ignition coils not grounding well enough. So every time I cornered it bumped up a little and lost ground. This meant that two cylinders were not firing. The catalyst will smell this and have the computer shut down the injectors on those two cylinders. The engine will then ofcourse stall. While coasting and hitting a bump it would hick up because of the same thing. When the coil falls back into place the injectors will turn back on. If this happends really fast, as in hitting a bump, the shtuuing down and starting up again will sequence so fast that it will feel like a hickup or a misfire. I lifted all three coils and made sure that when reinstalling them they were all firmly in place and I could hear then `click` into place. This solved my problem. The stalling or really rough idle at a standstill in R or D was caused by a broken wire between the air mass sensor and the ECU. I exchanged the meter for a scrapyard one and I still got the same error code on the computer. I then decided to put in a new one and this also did not fix the problem. Then the shop measured the current between the meter and the ECU and there was none. We found the wire broken. snipped it there, reattached both ends with the usuall duck tape and everything worked fine.
So I exchanged:
fuel filter, airfilter, ovp, fuel pump relay, cabled, boots, sparkplugs and the air mass meter just to find out that it was caused by a broken wire. These things are a nightmare. She runs fine now and I do not have to exchange a lot of things for the coming period. If the engine runs normal under4 normal conditions and you have a problem that occurs only now and then I can not imagine the HFM unit to be broken.
A hickup in the back of the car should be fairly easy to trace. There is not much there to hickup. There is the fuel pumps and the exhaust.
An idle surging betwen 500 and 600 rpmīs is, after reading all the posts, normal on these engines. When I stop the idle will fall slightly below what it should be and then pick up fast.
The surging in my case was a broken wire. Maybe you have a wire that is broken but still makes contact because it is inside a harness, maybe you can try to wigle the wire and see what it does to the idle?
Hope this helps in any way, dont by the expensive part yet, with these engines it is usually something silly.
Greetings and good luck,