My dad's 260E is one heck of a starter. I've always wondered why the 260s were hard to start as I found it to be a common symptom for most 260E owners.
The answer may lie with constant check on the plugs - as these creatures are highly sensitive to the plugs. Wrong plugs used, or dirty plugs may cause it to be cranky.
Next on the line - as you guessed right, are the fuel injectors.
For my dad's 260 - I had the injectors taken out and cleaned one by one. Put them on again, adjusted the CO for that smooth idling - and hey, the starting improved tremendously.
Okay, it still plays up once in a while. But its much much better.
The idling is another matter. I recommend changing the idle control valve.
126 tailed by a 203, 129 leading the pack.