My 89 740T has a couple of issues (may be related). After driving for 10 minutes or so, engine starts to have big misses and feels like not running on all cylinders. Idles rough and occasionally dies if revs not up high. After continued driving, seemed like problem went away. This has happended twice.

The other issue is when the engine comes down to an idle, it almost stalls and then goes back up to normal idle. This is a regular occurance.

After reading the FAQ's, I noticed the Hall switch was "hanging" from the distributor. It seemed to be plugged in but not firmly attached.

Ideas?????

-Mike

It's available from the dealer for a couple bux.
Have to pull the distributor to do it...will need a needle nose pliers.

start the terminals in the new socket, install the new socket, and use the needle nose to seat the terminals in the new socket. You'll need the play in the wires to install the new socket so don't seat the terminals all the way first!

Replace the O-rings on the distributor (just the two outside ones) while it's out.

If that doesn't solve the hot misses, it could anyone of a number of things from distributor cap/rotor to spark plugs or spark plug wires or ignition amplifier/module or engine harness disintegration. Have fun.

I had the problem you are talking about a year or so ago, where the engine almost stalls when coming back down to idle. It was a bad oxygen sensor (lambda-sond), which also ruined my catalytic converter. Checking the O2 sensor is outlined in the FAQ.