01 i30 t power fluctuations and dash lights. help!

[amber s]

Hi. New to the group. Have been researching on this forum for awhile trying to get some insight on what might be the issue with my i30. Have read some posts that have had some info. Sorry if this is a repeat question. Car was having power fluctuations when idling. Check battery and alternator at auto zone. Both deemed good. Bad MO weather. Cold. Wouldn't start. Jumped it. Start but wouldn't stay started after turning off. Bought new battery. Starts but battery, abs, and brake lights sporatically come on and off. Headlights won't work in on position only auto. Still having fluctuations. Read about bulletin regard air control valve and ecm. Also about maybe an issue w a motor mount. Does have one broken mount. It is driven carefully. My brother who is not a pro but tries usually does my car stuff. Ecm at autozone 400+ for refurbished programmed. Is the air intake hard for a non pro to do? Do I need an infiniti dealer ecm? Looking closely could I detect if its a mount issue? What about signs of alternator issue? So frustrated and may just trade in. Depends on how much to fix. So many problems w this car in a year and a half. Any advice in simple terms appreciated. Thanks in advance.