I thought that if your timing was too far advanced, you would backfire, especially upon accelleration. But, the backfiring goes away once warm...at least with the old ign. it did. Is there anykind of thermostatic device (like the kind that initiates the preheating of intake air by passing it over the exhaust manifold) that could have a vacuum leak--but only when cold?
03/83 300D 184k
07/73 280 160k