Engine miss when hot - where to start?

[911kiwi]

Stock 1972 911S 2.4 with MFI. Starts and runs nicely, pulling cleanly thru rev range when cold. Once engine is above 180 degs, engine develops serious miss to extent that it sounds like it's running on 5 cylinders.
I suspect it's an ignition problem - but where to start?
Car has petronix installed which been working perfectly.
New plugs, timing checked. Have new plugs leads, new dist cap so can try these.
Hoping for a short cut solution I guess. What ignition component loads up first when HOT?
One strange (possibly unrelated) ocurrence is that when I do a tight left turn at speed, there's a slight hestitation in engine - as if fuel starvation - have a new fuel filter to install to check this out.

Any suggestions welcome - plan to work by process of elimination today. (Searched this forum but nothing matched)
Thanks,
__________________