I was looking at an 89 Formula 305 TBI L03 tonight tht I am thinking about purchasing. When I checked under hood there was a mild grinding (although that description is not quite correct) a noise almost like the sound of a bearing going bad, you could hear the tone change when you grabbed the cap. After I drove the car which had good power (considering its an L03) and no apparant miss in the timing, the sound was gone. Any Ideas. I did not pull up on the distributor to check to see if it was loose I will call the guy and tell him to check that. Outside of that any ideas??

 

Of course first check to make the distributor bolt and cap are tight.

It could be the distributor gear going bad. Distributors do wear out and are not too expensive to replace. Others will know more than me but I think it is a good starting point.