On my 2002 MCS the F3 fuse under the hood is popping as soon as the key is switched on. I found out it controls: Camshaft position sensor/O2 sensor before cat/O2 sensor after cat/Solenoid valve, fuel tank ventilation/Relay K19 control power. I check the wiring on the O2 sensors and they are good. Some of this other stuff I don't know how to check. Anyone else experience this? The car is not drivable in this condition. I have not made any mods lately, this just started out of the blue...

Thanks.

 

Upon closer look it was the wiring to the O2 sensor before the CAT. The wiring was against one of the hoses with the aluminum shielding which had rubbed through the protective sheathing and insulation. I pulled the wire back away and taped it with some good 3M duct tape. All is well now.