Hello all I’m after some advice please, I have carried out a engine swap from zetec 1.8 to a standard ST170 engine specs below, I have a flat spot around 3000rpm under load, pulls fine up to & fine after the flat spot making good power, it’s always been there but seems to be getting worse recently

ST170 engine (standard)
ME221 with ST170 loom
running with VVT
Jenvey throttle body’s
Correct inlet manifold
Rolling road setup (2 years ago) 176bhp

You need to have a look at fuelling, vvt and ignition tables, see if there are any changes happening at 3K
It seems a lot of tuners don't understand the VVT side of the ST170, even the basemap from ME had advance increasing with RPM, which was not a great idea.