560sl won't run, help!

[lawrenceR]

I've had a terrible time with my 86 560sl, first chasing a rough idle, mucking around with it, throwing parts at it, and now the bloody thing barely runs at all. Would appreciate any comments.

Started out addressing rough idle, so replaced plugs, wires, rotor-no help. O.K. then replaced injectors, sleeves, o rings, air distribution hoses, no help. Then replaced intake manifold gaskets, throttle body housing, thottle position switch, fuel distributor o ring, fuel filter, vacuum lines and vacuum connectors. Replaced over voltage protection relay. NOW IT IS WORSE. Swapped idle control unit with spare, no differnce. Swapped fuel distributor with spare, no difference. Pulled fuel pumps, seemed to run fine. Fuel pressure test was fine. Drained tank, had clean gas.

Test revealed that it was only running on 5 cylinders. Compression test OK. Now the vehicle will start up instantly, run not bad for the first few seconds, then start running really rough, on perhaps 4 or 5 cylinders. What's wierd is that if I connect the electrical connector to the side of the fuel distributor, I think a fuel flap sensor, the car won't run at all. With this part disconnected, the car will at least fire, but go through the above sequence.

Before I started mucking with it, the car would idle a bit rough but ran very clean and strong otherwise. Smog report showed excellent emmissions. Looks like past owner did the heads on the car.

When I did the intake manifolds, I was a little too carful with torquing the intake manifold studs down and it burned white and made lots of smoke. Then idled at 2000 rpm, but smoothly. Re torqued everything, still burned white for a while, but smoke went away except for a little bit still. I had a bit of a problem getting the throttle body housing-the rubber air duct- with the throttle body causing a big vacuum leak, but now that is on properly.

Where I'm at now is the car will fire instantly, with the connector removed from the fuel distributor, run on all cylinders for a few seconds, then run like crap.

Where do I go now? Please anybody, I want to drive the car into the lake...
Regards, Lawrence.
BTW, this was a "cheap" ebay car, CA with 117,000 mi.