Uneven Running - 500 SEL runs roughly when in neutral

[Eddie Corr]

I have an '86 500 SEL which has now ran roughly on 2 different occasions, it doesn't do it all the time. When in neutral the engine runs a little roughly, like it is misfiring intermittently. I thought maybe it was idling too slowly but it still does it if I rev the engine. It has new plugs and air filter and the ignition leads are OK in that no arc-ing is seen in the dark. I haven't done the 'darkness test' with the plastic cover removed from the distributor or checked the rotor arm yet. Anything else I should be checking?

 

[David Halsey]

Uneven Running

Eddie,

Even if there is no arching there may still be a fault with the leads, also, when where the plugs last changed? what is the condition of the dizzy cap and rotor?