Diagnostic ~ Starting Issue....???

[Verdamn]

1990 Audi 90 ~ This has been coming on a month or so. Short trip - go to restart, fires instantly once and disengages starter, does this 10 or so times ~ but not on every short trip. Usually find that once frustrated, some accelerator would reliably ease and start, tho' never used before in 5 years.
The last week morn starts are o.k, but then when backing up (idle under load), engine/car surged like way to rich and idle control comes on an off..? O.k after few minutes & warms up.
I have replaced (planned maintenance) Dist.Cap, Rotor, cleaned plugs (outer rim sooty), Air Filter (cleaned housing, crankcase vent pipes etc.), Oil & Filter, checked all the plug connections yesterday and now it's extremely hard to start even with some accelerator with this same fire once & disengage starter.
Once going seems to run perfectly and starting doesn't seem to change warm or cold .
Just to confuse the issue, I did note on one temp..? sender that of the usual 3 wires on 4 pin terminal plug 2 had been cut off.
It's given me the impression that 1 cylinder is firing before the others are ready to kick.
Could that be a cold start valve problem, leaky injector or timing somehow has advanced....
Any clues, experience for diagnosing...?