Is it turbo??
i installed a walbro 255lp pump last night and then test drove car. first 5 miles car was great. pulled nice and hard. then it went to shit. it would go way lean when idleing to the point to almost dieing. cruiseing it would get really rich (12:0) then lean (18:0) and back and forth. my fuel system is completely stock except the new walbro... what is it?? pump?? fuel pressure regulator??