I am having timing problems with my 84 240gl b23f lh-jetronic. I am hopping i am at the end oF a long road to having my brick wheelin full speed. I have, over the past 6 months, changed all gaskets/seals from the head up,replaced coolant temp sensor, knock sensor,oxygen sensor, throttle switch, distributor, coil, wires, plugs,rebuilt idle air control valve,cleaned throttle body,become a master at adj.throttle sw, adj valve lash, replaced all of my vacuum lines and added clamps to all intake and emission hoses. All of these actions have had an effect on the cars performance, some helped, others seemed to expose/exacerbate different problems. I have also spent a good bit of time mending and replacing damaged wiring, so i feel fairly confident in my electrical system's integrity. By now, the car runs pretty well, I just have one small problem. I get this hesitation when i hit the gas from a standstill, engine idling.The idle is also a little rough. Sometimes it is a momentairy studder other times, it sounds like it is choking on something, at which point, letting off the gas slightly will cause the engine to pick up and run normaly. I should also point out the the car runs wonderfuly otherwise, 24mpg city, breaks 75mph without a sweat, and seems pretty quick from a stop and in traffic. As best i can tell, I have traced the problem to a timing issue. It seems to me, from watching my engine with a timing light, for some reason the ignition control tries to retard the timing at idle. I noticed this after about a dozen attempts to accurately time my engine. I have found that when i would put the timing mark around 10'btdc and tighten the distributor lockdown bolt, I could see the timing mark jump to 1'btdc and back. As it did this, the engine would stumble and sound like it was misfireing. The random sputtering at idle is reflected in the timing mark movement. The rough idle clears up and the hesitation lessened as the idle is increased, although no real effect until about 1100rpm. Also as i watch the timing mark, I notice that as i slowly increase engine speed, the mark will stabilize and advance in a typical fashion.
Having said all of this, i am wondering, why would it retard my timing at idle? Dose this make sense to anyone? I need help on this one, I have come so far, and, I am so close. Thanks for your time, kennethcardell