please direct me to another thread if there is one, but i couldnt find what i was looking for.

my05 sti - exhaust, gay bov and verso tune 262atw.
but i believe that was all done some time ago. the car has now done over 150,000. is there a set time/number of kms before a re tune is recommended?

it has always run rich in the four months ive had it, a good tank of fuel is 300km+. but about a week ago, a car savy chick reckoned it was sounding a tad off. me being me was thought nothing really of it.
then two nights ago it was idling high. thought maybe just because it was cold, didn't drive it long enough for it to properly warm up.
then yesterday sitting at the lights on the way to pick kids up from tafe, it starts doing a bit of 'rotational idle' (900-3500-900-3500rpm...over and over again) but as soon as i tapped the accelerator (green light) it was fine again. and it didn't do it for a few more lights, but then rolling down a street, clutch in, and it starts doing it rolling along? not as aggressive this time, 900ish to about 2600rpm, turn into my street and sit on the driveway, to see if it will do it again, and its perfectly normal?

anyway driving to uni today it was fine. on way back it started doing it again, then at last set of lights, it starts running really rough, missing, and engine light comes on. and i tap the accelerator and its gone again, but engine light stays on. so drive home super carefully, and sitting on the driveway it does it again, run rough making the whole car shake like it has mad cams, so try hold revs at about 3k, but there not very steady and its miss firing, and then all of a sudden its back normal again ?

i know there is a problem, but the lack of consistency is annoying, ill show someone and it wont do it haha. ive been driving it around pretty timidly past few days (heavy rain/traffic recently, and not very far)

thinking timing? in need of a retune, maybe shitty fuel or dodgy afm.
im not really sure, any opinions, previous experiences, solutions appreciated.

cheers robert.

Edit: shitty idling, loss of power & response and missing were caused by dirty throttle body solenoid. Thankyou Steve at maximum motorsport.

Edit: subaru wangara also had a look at it haha