My 72 4.5 W108 is driving me nuts.
I've replaced tons of stuff (plugs (bosch W7DC), Bosch points cap and rotor, all have 1000 miles on them), a shop cleaned the trigger points, fuel filter and tank strainer and cleaned the tank), set the timing, dwell is 33-34 degrees, new temp sensors (I and II), MAP sensor works well and checked out, new fuel filter, checked fuel pressure (right on at 30 psi).
I keep fouling plugs 4 and 8 (just soot, not oily or fuel wet). Should I second guess a good shop that did the trigger points cleaning and do this again?
I noticed yesterday that if I press down on the cap near the wire for plug #4
that the idle gets better instantly, so I put another wire in that spot but still idled like a fouled plug, even after cleaning plug 4. Could I have a defective CAP and ROTOR??
Could my dizzy shaft be THAT far off to foul plugs 4 and 8 ONLY? Could I have a bad new cap and rotor that I should replace? Wires are new too, by the way.
Don't the trigger points ONLY work fuel and NOT spark, correct?
When plugs 4 and 8 aren't fouled the car runs like a dream, but eventually they get sooty, like within a few miles.
Any ideas, MUCH APPRECIATED!