Alcapachino

A while ago i have posted about my problem:
https://www.miataturbo.net/diy-turbo...e-dies-103577/

So when i found a professional tuner and we installed a new Wideband + tuned the ECU properly i was really happy to have solved the problem!
For a week or 2 it was running smotthly then all of the sudden my rev counter started jumping up and down again ...oh no..

Problems:
- Dying out on idle after rev counter bounces crazy lke 5 times (runs ok first few seconds , so not instant dying)
- When blipping the gas and running car will jutter and stutter badly when keeping it on 3-4 k rpm in a straight line (undrivable)

I dont get that:
- Car ran fine, then i had this problem , fixed it with tune and 2 weeks later runs bad again?
- Im sure it was tuned properly, we spend a whole day tuning it till it ran nice and it kept running nice for 2 weeks with no problems (2nd time it has been tuned already)

My tuner has Covid so in the meantime im trying to collect as many suggestions as possible....help would be appreciated..Why does my car go back messing around? The tune is good.

MS2 ECU
1.6 NA '91
300 zx turbo (TB25)

Recently done :
- New Spark plugs

Long story:
When i bought this car it had severe throttle lag which i kind off solved with a new TPS etc. After this i had the car tuned properly and ran fine. Then the Idle problem and jutter and stutter came. I had it repaired by putting a fresh tune on it (by a tuner) and drove fine for 2 weeks. Now i have the same Shi*t again. I dont get it and my tuner has COVID. I realy hope some of the suggestions can help us once he is healed from his COVID.

Thanks for taking the time, i know it might sound like a weird story i have attached the vid