The 91 740 we just bought has a horrible shaking that comes on as soon as you bring it to a stop and try and sit with the brake on and the car in drive. It starts and builds within seconds of bringing the car to a stop. It doesnt ever entirely kill the engine and all works fine when rolling. Any help would be appreciated TIA H

Thank You for the advise-I am hopefull my problem has been diagnosed. Wish i could say we did get it fixed- but its just too cold here these days.

I has the same type of problem. At a stop sign the engine seemed to buck a little, so I had to keep my foot on the brake and also keep some pressure on the gas pedal. I brought it down to the shop, cleaned the injectors and end of
problem. Hope this helps.

I have a '91 745, fairly new to me, with the same symptoms (well, since I fixed the idle so it WOULD idle at less than 2000RPM. It is much worse in gear than in park or neutral. I was thinking tranny mount, but when I bothered to look I saw that the fan is actually resting so low that it hits it's shroud and is wearing grooves in it's blades. That isn't the cause of my vibration, it is another symptom of the real problem. My engine mounts are shot and the whole engine is sitting too low and is no longer cushioned because of the bad mounts.

Check out the FAQ for engine mount diagnosis. I ordered new hydraulic mounts from Groton ($45 each and you need two). I THINK me and a buddy can do them ourselves.

Best of luck,
Andy
'91 745 Regina 184K, '89 244 135K, '87 245 lost the rust battle at 225K

Check your inlet manifold gasket. Can you hear a sound of air being sucked in (a sort of hissing) when the car idles ? This can lead to very rough idling and motor bucking around at idle, but OK performance at higher speeds, due to the change in manifold vacuum.

John Marshall
1994 940GL, B230FB motor, manifold leak/ rough idle.

is this only with the brake applied?

right--when in drive and stopped ty

sounds like an internaly leaking vacuum brake booster. you may or may not hear hissing whith the brakes applied. If you idle the car, then turn it off, you should still get 2 or more power assisted stops, for hours after turning off the engine. When restarting after pumping the pedal a few times, the pedal should sink under your foot as vacuum rebuilds in the booster(if it doesn't, the booster and/or its hose are dead. disconnect the booser hose at the check valve(you should only be able to blow through that one way), and plug the hose with a socket extension or bolt... Your braking effort will be much higher, but if it solves the stalling, you have located your problem.