Hesitates under acceleration

Thought I would let people know how I got on - might help others.

Bought the car from a mate - late 80s Mk1 GTI Cab 1.8 8v.

Car was difficult to start and sometimes it went ok… other days it felt like the choke was pulled out and that it was trying to clear itself.

Was a bit of a journey of discovery… most things i changed resulted in slightly better performance, but it would still not run correctly until the last 2 things that I changed.

1. Changed plugs, leads and reverted back to original dizzy cover. - No real change.
2. Changed air filter and coil.
3. Changed fuel filter.
4. Changed lifter fuel pump and removed some slight rust from bottom of tank with magnet.
5. Changed mixture setting - car ran better and started straight away.  But some days it still felt choke was out, and slight hunting on tick over.
6. Changed all 4 injectors, seals had gone on several.  Slight performance improvement.
7. Changed main fuel pump.

Now starts better, runs ok,  but every other day - would run cr4p…

Began to think that it had to be running different mixtures on different days causing it to run ok on some days and cr4p on others.
Started to look at the Warm Up regulator - and could see that it changed fuel pressure etc,  Could this be it?  Peoples problems with the WUR from searching appeared to be more start up related issues - not running issues….

Purchased a refurbished second hand one, plus the associated temp sensor and fitted them today.
As soon as the car started - I could tell that was it.  Really clean idle, no hunting.
Took it out for a spin… it had never gone as well as it did.  Really pleased.  Is twice as good as when it previously ran ok, lots of power from low revs.  Although it was not cheap, in my case it was well worth the cash.