engine light...02 sensor
 

I went to smog my car 96 civic. was told both 02 sensors were bad. replaced both, reset engine light, and now it comes back on, with it reading bad 02 sensor 1 is bad. replaced spark plugs, still nothing. any suggestions?

have aftermarket i/h/e??

maybe your cat is bad or something?

no aftermarket stuff, all stock.

leak in the exhaust before the O2 sensor?

here a high pitched hissing noise when taking off?

how many miles on car?
car run very hot?
car run ok?