if you sprayed anything on the O2 sensor will it damage it?

I say this because the guy att he muffler shop sprayed something over the sensor. WOuld this damage it ?

also would the size of the flexpipe make a difference in sound?

 

depends on what he sprayed on it, did he spray it on the threads or the sensor part.

they can be pretty sensitive and are important for good performance and economy.

i don't think the size of the flex pipe matters.

 

i believe on the sensor part...

 

again it depends what he sprayed on it. Did he do this on purpose? If so might have been some sort of a cleaner that is used to help keep the sensor clean... You should have asked him what it was he sprayed on there.