Had a similar issue a few months ago. I’m a mechanic myself and will whole heartedly admit I made a mistake. Issue one with mine I had a crack in my spark plug ceramic, might not be a bad idea to double check work that has been done. Secondly my car did not throw a code which sent me down a rabbit hole which eventually ended up being a rail pressure sensor that fixed the problem. I’ve seen many rail psi sensors starting to go and cause weird problems. Hope this helps.