Im going to try explain this as best as I can and I need some help in trying to solve my problem. I have a 97 TE (Yes the reputation of problematic Magnas) that's been plaguing me with the same problem. It has a very high idling problem.

It first started after driving the car at high speed and when I was parking, I noticed when I switched to reverse the car seemed to want to bolt backwards and it jerked quite strongly. I looked at the idle and it was on 1.2 (on Idle), I switched it to Neutral and it rose to 1.8 - 1.9. Whilst in neutral I revved the engine to about 5000rpm for just a second and let it go and the revvs came back down to 0.8 - 0.9 as should be in Neutral. Took the car for a spin and I noticed the gears were shifting really late when stopping and even to the extent whereby I would stop and 2 seconds later the car would shift down and jerk forward (with my foot on the brakes!).

At this time I had little money but I didn't mind as I was going on holiday in a few days so I simply parked the car and left. Arrived two weeks ago, car behaved for 3 days and was back to the same. This time the revvs went as high as 2.8 in NEUTRAL AND PARK! And when I drove it the shifting before a stop was terrible and when I wanted to reverse it seemed like the engine wanted to jump out and run. Got the mechanics to have a look at it and run it on the computer and said the fault code was 'air flow sensor'. He also noticed the throttle butterfly was sticking at idle. He cleaned it out extensively with a wand and cleaned the air flow sensor. He said that there was a lot of carbon build up which was funny because I had performed (well the same company which I use for repairs) a 3 in 1 fuel inection service about 2 months ago. When he was done the car was fine. Idle was at 1 and in D would fall nicely to 0.7 - 0.8 (this was two days ago). Came back home today and the cars started the same thing. I don't know whats wrong now? I have a feeling its the idle control valve fault or maybe the O2 sensor?

Anyone had a similar problem or have any ideas what it could be? :( I'm thinking of maybe trying to get some second hand parts from the wreckers if brand news are too expensive.

o2 sensor will not do a thing for the idle, just seems to be a word people like to bad around when they have issues

Can be the Air Control Valve, also when it is at high idle,grab the throttle and see if you can close by hand, if so you have either a cable or throttle shaft geting stuck. Air control valve is another big issue, especially on a filthy TB.

Just because the injectors were serviced does not mean that the TB was done or done correctly either

Sounds like a bad IAC Motor or carbon build up in the IAC Port in the throttle body.
The only way to clean properly is to remove the throttle body then remove the IAC Motor and clean the airway.

I don't know if I should attempt to clean it myself, not sure how complex the procedure it but I could follow the repair manual step by step. Alternatively I'll have to get a new IAC motor (which i've been suspecting for a while) and see if that makes any difference. Does anyone know the part number for them and an approximation of how much they should be?

The stepper motor will not cause this issue generally, is more the air valve that will do this

just an update...FINALLY figured out what the problem was. A mixture of the throttle body and the IAC. Got a 'cheaper' second hand Throttle Body (IAC included) to test it out and hopefully IF it fails again later down the track I'll know exactly where to go. Got it installed today and the car is great! Finally showing me exactly why I bought it. Idling is great, transmission is working much better as a result too!

Now I can finally begin saving on those lowered springs I'd been wanting for a while. Thanks Madmagna & Little Red Wagon! :)

EDIT: This thread is now officially closed