Strange rumbling noise suggesting faulty front wheel bearing

[Yorkshire Engineer]

Typical event: Travelling on a flat road at 50 mph with a very light accelerator. Rumbling noise that seems to be coming from nearside wheel.
Wheel bearing passes MOT type backlash and wobble test.
Probable cause: late detonation of fuel in exhaust manifold. Producing pulse jet type sound.
Root cause: worn out HT leads. Will typically show as insulation on 500V tester.
Solution: replace all 5 HT leads.
Caution: there are at least 5 different distributor caps, each with their own style of HT connector. GM spares computer does not know which cap is on a specific car.
Applies to: 2ltr SOC multipoint petrol fuel injection. May apply to all with high energy ignition systems.