idling and inevitable stalling issue on 89' 740 estate

[userxer0]

hey guys! So, I'm considering buying an 89' 740 estate, but the only issue that its having is a rough idling and inevitable stalling issue. After talking with the seller, I'm convinced that the problem stems from the IAC valve because of the way he described it to me (idling fine at cold start, then after like 15-20 mins of driving/ or on warm starts, it begins the idling erratically and eventually, if not given gas the idle will drop and stall out.) he also stated that he has tried cleaning it. He said it helped a little but eventually reverted back. Some of the parts he has replaced include a new fuel pump, strainer, filter, and fuel pressure regulator. Oh, and after it stalls, it fires right back up if given a little gas/ mashing on the gas. So honestly, with all of the researching that I have done so far, and just based on my very limited knowledge of the 700 series all of the symptoms point to a bad IAC valve, but of course those combined symptoms could be the cause of a multitude of different things. Any advice or guidance on this issue would be so appreciated, because I really like the car, and i feel it could be an awesome daily, but just don't wanna get myself into anything that I can't really handle lol!