different idle problem after new stepper motor

[mivecboy]

Pumped my brakes a few times so dont think it is the brake.

[bigpitty1]

its probably not the brake booster then.

[payaya]

its not your ISC i cant see if being the problem. Maybe when idling or cold but when there is dramas with revs bouncing while driving then is TPS related.

Test your ISC just in case measure the resisitance betwen coils when cold AND WARM!

[illmotion]

I ve replaced my stepper motor few weeks ago due to idle die out when cold and when aircon is switched on.
This has fixed the problem but I'm experiencing another 2 issues:

1) idle will bounce up and down between 900 - 1600rpm when doing half to full steering turn whether stationary or moving.

2) When cold start, idle is very high at 2500 - 3000rpm for few minutes, then it would bounce up and down between 1500 - 2100rpm for another few minutes before it settles down to normal idle rpm. I remember back when my old stepper motor was working properly, cold start did not go above 2000rpm. So reving at 3000rpm when cold is not doing the engine any good. What does your FTO revs when cold?

I've resetted my ecu twice with no cure to the above problems
please advise?

I got the exactly same problem as you but the other way around my old stepper used to rev very high at cold starts, but the new one i bought from taz idles out when starting the car with a cold engine.

[Taz]

plugs.
if theyre the wrong rating it can cause this issue

[Taiwo]

I had the same problem after getting new stepper motor from Japan. Take it to mechanics. It cost me 200-$300 to get it fixed. Turns out it was the ecu n electricity overcharging each time.