Hi, i have problem with my E34 1991 with M50B25 vanos 1993 (previous owner swap). I have replaced so far:

spark plugs
coils
MAF
all temperature sensors
camshaft sensor
crankshaft sensor
injectors
O2 sensor
knock sensors
ECU
TPS
fuel line, fuel filter, fuel pump pressure is 3.2 bar
no air leak (i did smoke test)
no smoke at warm weather
vaccum in intake manifold -0,49bar ~375mmhg

a month ago I changed lifters and checked timing

I will be very grateful for any tips.