Hey Guys and Gals

Im having problems with this old Sigma (Diamante) 1991 SOHC 12V with manual tranny.

when its cold it runs great until it get to operating tempeture 2-5min later it starts to bog down and it runs very ruff and is completly unresponding with the throttle jumps betwen 500-1500rpm and the coverter get glow red, allready blew one

its running very rich like running with "choke" on all the time

We have replaced
Sparkplugs OEM
plug wires OEM
cap and rotor OEM
Coolent temp sender OEM
Oxygen sensor OEM
MAF OEM
ran it downpipe only
Read codes nothing

anyone got ideas what it could be????
we have talked about leaking injectors

Thanks
Thomas
Denmark, Europe