'81 4k no start

[Keith Lawyer]

'81 4k, 1.7l (hey, it gets me to work!)

-first noticed occasional "surging", ie at part throttle it'd be a bit
underpowered and then "snap" back to normal, without changing throttle
position

-next morning would start but not idle, had to restart numerous times
(whenever I pushed in the clutch)

-then underpowered on hiway, ran very poorly

-finally could not get it to run for more than a few seconds at near
WOT, almost as tho timing was way off?, would run very rough and die,
exhaust smelled odd - stranded!

-now will not start at all but sometimes tries (cranks fine)

Last nite I verified it's getting fuel and spark at the plugs.  Plugs
look good as does cap/rotor. Air filter looks good.  Large black boot
from filter to IM has some small cracks forming (not all the way thru)
but I can't believe this would cause my symptoms on this older CIS??  I
"scrunched" the boot together while the gf cranked in an attempt to seal
up the cracks but it made NO difference whatsoever.

How sensitive are these cars to vac leaks?  O2 sensor doesn't come into
play during cold cranking, does it?  Is it possible I have a problem
w/vac advance on the dist?  Come to think of it, what drives the dist on
this motor (it sits so low?)?  Are these interference motors, never did
look at the timing belt!?

Thanx!
Keith L