Blue label coils on a 104 are just junk. Pretty easy to spot, remove the cover and if the part number labels are blue, toss 'em. MB had a SI on these at on point. I've never had anything but trouble out of 'em. The lastest version is square bodied flat recessed top. Seem to be pretty dependable from what I've seen. Just replace the resistor tips at the same time.
Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.