The Idle is not so much erratic but jumps up to anywhere between 1100 to 1500 rpm and sticks there rigidly. This is usually only when the engine is up to temperature and can settle back down to normal now and again.
It did have a cold start problem in addition to the above so gave BMW the shirt off my back and fitted a brand new ICV. Cold start is now fine but high idle is still there. Blue temperature sender has been replaced and most of the pipe work. No vac leaks present.
Finally when the fast idle is present if you rev the engine it will take forever to drop back down to even the fast idle. i.e. the revs stick high between gear changes.
At worst it will do 20mph + in 4th gear with your feet off everything. Properly annoying! Plus if I stop at a zebra crossing I get several disapproving looks as it sounds like I'm on launch control.
But it will.....and without warning occasionally go back to running completely normally. So confused!
I'm leaning towards TPS. I can hear a click when moving the throttle body off closed but it seems to fit the symptoms. Plus the throttle body feels a little notchy.
Has anyone come across this? I am happy to swap out the throttle body and TPS but given the assault on my bank account from the ICV I want to be sure I'm in the right neighborhood.
