1990 Sovergn, 175,500 miles. Rear cylinder misses at idle. Doesn't seem to (or I can't feel it) miss at any other RPM. Checked: Plug, SP wire, compression, injector. Haven't checked as I don't have the equipment, the injector wire and contact or the control module.

What else should I be looking for? Is it likely that the injector wire or contact clip are bad?

I originally posted this on another board as a SJ6. Just dislexia or something.

Lanny

 

Did it again. I own a XJ6 that the rear cylinder is not firing.

 

You have done the basic checking as I would perhaps suggest.

When you "checked" the plug, was it the "correct" colour, or all sooty and showing it is not firing??. I would place a spare spark plug in the end of the lead, with that plug jammed in such a place as to provide an earth path, start the engine, see if you actually have spark through the lead. If so, then the lead is not a suspect .

If the leads are the originals, or of unknown age a new set would not be false economy in my opinion.

A new set of spark plugs may not be silly either.

If the above proves spark, then it will shift the search to the fuel area, and yes the injector and its associated lead would be suspect. A sticking injector may be the culprit, so again, with the engine running, use a stethoscope (or similar device) and listen to each injector, then listen to the rear one and see if the "click" is the same. This will eliminate the electrical portion, but just because it "clicks" does NOT mean it is actually delivering fuel, but it will get to the root of the problem without throwing heaps of money at it.

Others will chime in with specific ways of testing injectors etc, but this way works well for me with the mighty V12's, and some of them only need a little persuasion with a hammer to get them doing what they should, and all 12 are back on line.