Miss firing miss when slight accleration has gradulely got worse

On a what?

Changing spark plugs, doesn't make it worse

Best to have a shop road test with scan tool
& look at data

Check plugs leads , compression , Check petrol pump , And filters .

could also be something as simple as plugs or plug leads

Is the check engine light on ?
The engine could have a slight miss-fire which would be made worse by the load of the a/c.

Could be a long list of choices.
Nothing special happens when the ac is on other than the extra load on the engine.
You probably have a slight miss-fire most of the time and the ac makes it worse.
A miss-fire could be a faulty spark plug, wire, coil pack, or injector among other things.
Is the check engine light on ?

It sounds like its a coilpack. Its hard to say whick one, but it can have hot fire running slow. Then when the demand go's up and running faster it fails. So it might be a little expensive but I would go ahead and replace all of em. Prob lesss than 100 tho.

hi when was the last tim the vehicle had a service? could just be that it needs new spark plugs,fuel filter could be slightly blocked i would start with a general service first

its miss firing get it to a shop ASAP or get it towed before engine gets hurt internally

i would check the fuel lines make sure you didnt put a kink in the line

your mechanic must know if its misfiring ,has it got coil packs on top of the plugs? or ht leads from a coil pack,also check for air leaks..