How would I no if I need a cat r a O2 sensor o 2 sensor

Not sure if we need a total brake job or just need brake pads. Would like the worst case scenario please.

When I turn my radio up it blows fuses and my dash lights quit working along with brake lights and/or the whole right side lights

when I bought it I was told it idles rough when it got hot and it was because of the intake hose is this correct. When its not hot it does not make the knocking sound at all.

both oxygen sensors bank 1&2 at 35,000 miles, the service engine light returned again,the car runs fine, but I need to have the car smogged, What should I do next. By the way the car now has 109,000 miles. Appreciate any help.

The "check" light, not the "check engine" light turns on if I try to drive it on the freeway. It starts to blink and then stays on for a little bit, before turning off completely.Any help would be greatly appreciated, thank you!

especially while accelerating after being using the gear to slow down

I have a 91 and the check engine light is on, they wont let me smog it with the light on, has anyone else had this problem? please help

Or if there's any other way thank you

I went to put a new headlight bulb and get the cover off and the wiring is melted and will not work with the new bulb in it. How can that be fixed?