1973 450 SEL injectors not clicking

Hey all~

Yesterday, I removed the Bosch Platinum plugs and when examining them, I found that they showed signs of cylinders running too hot. I replaced the plugs with Bosch Copper core plugs.

I drove 2 miles and suddenly I get this loping feel. So bad that it sounds like maybe more than one cylinder is misfiring! I could barely make it up a hill, I pulled over, revved it: *poof* loud bang and a plume of black smoke out my exhaust, then it ran okay and I drove it one more block when it started again and I parked it.

I remove the plugs. They are covered with black soot. Some plugs are slightly moist. I start the car and it lopes like a misfire. I check all the cylinders and make sure the are getting a spark from the distributor, I re-gap the points, and I check the wires with a dwell meter to make sure there's voltage in the wire. Everytime the engine loped the voltage would drop off (probably fom the lope). I also checked the vacuum advance and it works fine. Othr vacuum hoses seem to maintain proper pressure. I put a stethoscope to the injectors. Sure enough 3 of my 8 cylinders injectors aren't clicking. I messed with the Emmisions Control Unit (ECU) earlier to make the misture a wee bit richer or leaner because the MB tech told me it may be running hot from a lean mixture. 1-800-222-0100 option 7 and asked to speak to a tech.

This has happened before to me but this has been the worst case. Before I simply drove out of it but now its time to fix it. I wonder what is causing this? I still have to try attaching a noid light to the connectors. Is my ECU bad? Is there a vacuum leak I wasn't aware of? Is there a broken wire or controller? A sensor?

Funny enough, I backed it out of my driveway feeling hopeless and sure enough it was running fine again. 2 hours of hell and now it ran okay! I didn't want to chance it though so I parked it, ran to my computer and here we are.


Ideas on this or my overheating problem? 1973 450 SEL running hot at high speed


Thanks for any input!