catalytic converter question

[jasonkec01]

i've searched around but am unsure if my theory is correct.my cat is probably original,after 200k and 22 years.my question involves performance and the 02 sensor. i'm thinking now my 02 sensor could've overheated because of a crapped out catylitic converter.the day/2 before i began having all sort of performance issues, i put in a bottle of LUCAS INJECTOR CLEANER on a full tank of B.P.[amoco] high octane. i always use premium gas and less than 5,ooo miles ago had the injectors replaced. i've removed the # 1 plug and it looks great. my oil smells gassy though and i honestly can't say if i remember oil ever smelling gassy before....... so, heres my theory... my cat is bad,i clean the injectors and that frees up a bunch of gunk sent to the cat which is already shot or very close too. that clogs up the cat much worse, overstresses/heats the 02 sensor/burns it out.........i end up with crappy performance.............am i going somewhere besides the wrong direction ??? i've got enough into this car already to have put my kid through college...not too excited to do much more than i have too. !