I've done enough miles in Jegger lately to finally get him dirty for the first time in years. There is (inevitably for a Ford with over 100k on the clock) always a transient fault or two going on. Today was the speedo that decided it couldn't be arsed this morning and decided instead to just make a speed-dependent grinding noise behind the clocks. However, later on, it decided it had finished it's sabbatical and burst back into life. Self fixing faults are weird.
The other issue that won't go away is the tracking. I've reported a few times that 'Yay! It's finally sorted!!!' but the truth is that whenever I subsequently drive another road, the steering seems all mucked up again. Now I know it's all tracked up and the tyres are still half decent, but the steering wheel still wriggles and and squirms over uneven roads and poor surfaces. The best way to describe it is that it seems to move diagonally without steering input. Almost like the rear is steering the car and the front end is following suit. Steering corrections almost always end up in over-correction and a counter correction is needed.
What can screw up the handling in this way? Is there anything that causes these faults (other than the rear bushes which have been changed)? Can the rear spacers dissolve and cause movement? Bit stumped and it's spoiling an otherwise perfect car!