Golf 1993 cabriolet 1.8i Kjet running lumpy /misfire issue

Hi peeps
I need some advice please I've been driving my cabby since March with no issues I left it on parents drive for 5 days.
Last weekend I picked it up to go for a drive out car started first time choke on everything fine choke went off and car started idling lower than normal drive her up the street  and she felt really lumpy and I notice popping sound from exhaust and what sounded like misfire.
So I've changed all plugs new leads and new dizzy cap and rotor had the car checked  this weekend  by a tuning guy who has set the timing checked CO he said everything is set correct and timing was out.
The car seemed to drive better but there is still a problem.
When on choke everything is fine when off.Car seems to hold back on acceleration and seems really bad at about 2-2,5 rpm almost feels like misfire  if you floor it car runs great and quite smooth I have run some expensive injector cleaner through it to see if it helps but doesn't seem any different  as anyone ever had this issue or can anyone help the guy who tunes car said it sound like injector I'm not sure everything was ok till I let it sit for a few days

Hi, just a bit confused by your post, you say you have a kjet 1.8 but you mention "on choke", there is no choke on  fuel injection?

I'll ask the obvious question first, have you checked the overall condition of your fuel system and tank for rust and debris. This is main culprit for most poor running problems. If you haven't done so already I would check this out first.

Sorry dude what I mean is normally when started first time revs are at 1000rpm for couple of mins kinda like auto choke then drop just under to idle limit if that makes sense
The guy who came to do the timing seem to think it wasn't fuel blockage of sort could he be wrong he seemed to know what he was on about I'm just stuck mate don't no where to look next I suppose I could check pump ect

Checked all your vac lines?

Yes mate he checked all them when he did timing no leaks all the readings he took were fine said the only thing he could think is injector maybe blocked a bit

Have you pulled the injectors to check for even spray and good flow?

No not yet mate I'm not really a mechanic so don't really want to mess with injectors will have to get him or some else to check them I can check the easy stuff lol

Are you running on super unleaded or normal unleaded as the timing has different setting for what ever fuel you use.
I found super unleaded better.

Is there an easy way to check that the metering head is working properly and doing it's job