I'd let your trusted mechanic do the work. It would seem that he isolated the problem. I'm not versed on fuel distributor removal; it seems to me in this case you should just let your local pro finish this one for you.
My 2 cents.
1991 300-SEL - Model 126
M103 - SOHC
James Madison - Oppressors can tyrannize only when they achieve a standing army, an enslaved press, and a disarmed populace.
Liberty Firearms Training - After years of trying to regulate California criminals with a never ending stream of gun control laws they have still not given up with the belief that if they make something a crime that criminals will miraculously start obeying the law.