So my buddy has an '89 bmw 325i. Yesterday he was saying his car would not idle, due to a cracked intake tube, so he replaced it and it idled fine. Today, he called me and told me that he started the car up, and his idle is fluxuating from about 1000-2300rpm. I haven’t seen it since so I don’t know what is working or not working. If I had to guess I would say it is his idle air contorl valve, or maybe his PCV valve.
So… yeah if somebody has a guess at what it could be I’d like to know, cause we’re gonna try to fix it on Sunday I think.