Mk1 Eunos occasional bad missfire...

[notax]

My girlfriend has just bought an early Eunos and whilst it drives well most of the time it suffers from an occasional bad missfire. This can happen when hot or cold (though more likely when warm) and happens at any revs and any speed. There is a slight oil leak from a little box at the rear of the engine - CAS? but no idea what this does and whether relevant. Is the best bet to start by changing the HT leads? Any other ideas?

[Oldandslow]

If it's ignition - plugs, leads, coilpack. In order of expense. Check HT lead connections first as they can be tricky to fit down through the cam cover and don't alway go on all the way. A loose one will weaken the spark. Does weather conditions/dampness relate to any of the times it happens?

The oil leak is probably OK but if it's dropping onto the heater hoses it can cause these to burst/leak.

[notax]

Thanks, we'll check it out. Today is the first wet day since she bought the car and it has been ok... not sure this helps with the diagnosis?

[mad4amanda]

very prone to ht lead failure start with those and check timing