It turned out to be the plug after all. No explanation as to how I missed it and a total mystery why the problem persisted, even after I swapped a known good plug in on the lame cylinder.

After I put everything back together again with the old plugs in different positions from the original, I noticed that #4 was now not pulling its weight, and, sure enough, the plug in there was the one that had been in #1. I put in the known good plug that I had tried before and the cylinder came alive. Same old story: it's the stupidest things that cause the most problems, that includes the guy who holds the wrench. I was so focused on my original problem - the mouse nest in the manifold that had caused the uncontrollable revving - that I wanted to rule that out as a cause first after the first plug exchange didn't seem to lead anywhere. That turned out to be a big waste of time and effort.

Of course, now I have a leaking manifold gasket that got damaged in the process, an idle that surges between 600 and 1400 rpm and won't settle down to around 900 unless I retard the timing to 10° ATDC. I'll take a stab at correcting that, but converting to SUs is getting more and more attractive. At least, I'll understand what is going on.

The car also has brake problems. I just noticed a leaking caliper and the hard brake lines need replacing - too much rust, and the exhaust system has had it. So, I'm beginning to wonder if this is a keeper, but I hate to be the guy who takes another 140 off the road. Although not pretty, the body is reasonably solid after a bit of patching, the rust underneath is not bad for a New England car that has seen mostly winter use over the last six years, that is, when it was running. The power train is in good shape. I guess I'll have to sleep on it.

Thanks again, for all the help.

Bob S.

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‘62 PV544 (B20, M41), '71 142E, '93 240 Classic Wagon, ’52 Ford 8N.