G'day, am new here so bear with me......own a 1994 Audi 100, 2.6L V6 (ABC engine) with 140,000km on the clock.Recently had injectors serviced,new seals and replaced idle-control motor (on the throttle body),also had one cracked injector so replaced it with second-hand item( couldn't source a new one here in Australia at the time). The idle-control motor was also non-Audi ( GM Holden item was fitted by local mechanic who said it fitted perfectly). A month later(and with the onset of colder weather) I'm having cold-start problems....takes a few goes before it wants to fire up...but always eventually starts. Secondly, the idle is staying high( like warm-up mode)@1500rpm for a long time and pulsing; even when the idle is at normal about 700rpm there is still a pulsing of 100-200rpm either way. AND... when driving or accelerating then lifting off the gas the revs won't drop for a few seconds then drop abruptly...really noticeable. Anyone got advice....could it be a vac leak? ecu issue? is there a cold-start valve or warm-up-regulator like on my old 100CD 5 cyl? Sorry for my ignorance....haven't had this car very long and have no manual or knowledge about code-reading. Any hints would be much appreciated.

it could be a few things Vac leak is a good place to start then there is the idle air control valve, throttle position sensor, coolant temp sensor, intake air temp sensor etc etc and so on but a code check might speed fault finding a little faster

Thanks Dave, I'll check for any obvious vac leaks,but fear I'll have to take it to the stealership to look for fault codes. Here in Australia Audi is still really a fringe marque and service backup has always been poor....especially for anything pre-2000 and other than A3 A4 or TT. Not many other mechanic shops have Audi diagnostics or experience, and a lot won't even touch your Audi. Thanks for the tips ...Regards Steve.