I've run into a intermittent ruff idle problem the past few days, but do to limited time i haven't had a chance to trouble shoot it yet. I'm working with a 1994 Land Cruiser. So far the problem seems to only cause the idle to drift up, and down between 650, and 475 RPM while in drive, with AC turned off. I've driven it far enough to make sure that it entered closed loop, and long enough for it to generate trouble codes. As a quick check today i was able to Pull the rubber air intake tube off between the AFM, and throttle body looking for cracks, none found. Checked for any loose or broken vacuum lines, none found, checked for any plugged or leaking vacuum lines on EGR system, none found. Listened to see if all 6 injectors were clicking/opening, all 6 were clicking. I put a scanner on it late this afternoon, but no codes were found so i plan to dive into this more tomorrow. Before i spend alot of time trouble shooting, do any other members have a quick source for this problem.