Hello. I've been having a couple problems with my '89 740GL with the B230F engine (non-turbo). The car is in great shape and has relatively "low" mileage (94,000 mi.) for its age. Anyways, I'll outline them here...

1. Rough Idle - When the car is idling it tends to "surge." It normally idles at 1000 RPM but it often "bounces" between 700 and 1000. Sometimes it will drop well-below 700 and shake the car and maybe even cause it to stall.

I used a fuel additive to help clean out any carbon build-up. It helped some. After doing some research I've come up with some possibilities...bad fuel pressure regulator, bad/dirty idle control valve, bad/dirty injectors, dirty throttle body, fuel filter, or all of the above.

2. My car has a strange problem with starting...it will ALWAYS start, but about half the time it needs to crank longer than normal (4-10+ seconds) while my foot is on the gas. I'm wondering if the aforementioned idle problem is related.

I would really appreciate any suggestions/help. Thanks.