Hi,

I have a 1989 760 with B280F. If I start the car when it is warm, the idle often surges between 500 and 1k rpm. It then evens out, but is very annoying. If I start the car cold, the idle is almost perfect. Could this be the IAC valve?

Thanks in advance,

Tim, Australia.

Check the FAQ'S and clean the throttle body as describe. A little clean-up will fix 90 % of that kind of problem. So you can check too all the vacuum tube, look for leak'S crack or spongy rubber tube.
--
(740 gl 89 (421 k km), 760 gle 88 (200 k km))

Thanks for the reply, I cleaned the TB a few months back, although I am driving the car quite a bit. Maybe it's time for a thourough TB clean. I replaced the rubber elbows on the vac lines a few months back, so they should be fine.

Thanks again for the information,

Tim, Australia.

760GLE, B280F, 224,000km.