b18c1 problems- 3 engine codes

[popimp6974]

i have a 97 civic with a 98 gsr motor swap in it, and when i was driving home today my check engine light came on. it threw 3 codes...20...41...65. if im correct they are the primary o2 sensor, the secondary and the load detector. why would all of these have ahppened at once. what should i try first. any help will be greatly appreciated. thanks

 

[popimp6974]

ok now my car idles at like 1600 rpm's instead of like 600 and when i turn my headlights on my dash doesnt light up. oh and my speedo doesnt work either but my tach and other gauges do. im totally confused.