Friend of mine has a my05 blob sti widetrack. He had eml come on and fuel gauge went down even tho had half a tank or so. It sorted it self out and and eml went out. Few days ago eml came back on. I plugged my psi3 data monitor in and showed no code even with eml light on. I reset ecu command and eml has gone off. Why would it not show a code? He has said he put tesco 99 in recently instead of his normal v power. Car still has all cats in place and no induction mods

 

Perhaps the plugs into the back of the clocks have a bad connection or are lose?