To all of you good people that have tried to help,with the start up noise on my 1980 450sl.As you may remember.Light knocking sound.only when car moving.In three to five minutes knoise would go away.Well a new development.This may give some of you enough info to pin point the problem.Yesterday.and today when I started the car and drove off NO NOISE.The only thing diffrent was that it was warmer.I know that the car has a cold start system among its many parts are an extra injector tha sprays extra fuel when it is cold.I am wondering if something could be messing up in that system,causing a lean run condition when cold and causing the knock.What do yall think.Thanks Michael