I've had a 'jerking' problem I've been working on since August when I swapped out my peanut cam. Replaced alot of stuff to finally discover for sure the problem was my cracked reluctor (cracked on the bottom- hard to see). It caused an intermittent miss on #3 cyl that I could see with the timing light. All better now, and drives like new.

 

what exactly is the "reluctor" and where is it???

 

At the distributor.

 

The reluctor is pressed on to the main shaft and has 8 points on it- looks like a star shaped thing.