I replaced the main cats/manifolds on my car 3 yrs ago with a set of used cats/manifolds (from an IS250--same cats for IS350) after the originals went bad. My cars engine burns oil as it should for 268K miles and Im wondering if the newer cats are getting clogged with engine oil and carbon buildup--theres currently no CEL.

Ive seen cat cleaners--DuraLube, Rislone, Catalclean, IDK if they actually work, Ive seen mixed reviews. Scotty on YT says use laquer thinner in the gas, another guy says remove the O2 sensor and spray solvent right into the cat honeycomb.

Or what I want do is get a set of PPE headers! But Im in CA with such strict smog laws. Is is true the police and state can impound your car if they find headers installed???

 

My cats hate when I try to clean them, I have scars from the last time I gave Bamdit a bath! Any other kind of cat cleaning is just snake oil.
California can cite you for any emission alterations, and if you are a repeat offender they can take your car for a month or 3 and they can even terminate your parental rights altogether. Headers don’t really increase emissions but they don’t care, you will not be able to get it inspected when the tags expire. Someone could snitch on you for the reward. Unless you have an out of state address to register your car then I would give up on your dream of PPE headers. Get yourself a nice exhaust tip, with the resonator in it?

 

If you’re in SoCal you’re fine… just find the right place.

 

Cat cleaner do work if used correctly. The 02 sensor spray works well. Also to continue to maintain them, use Top Tier premium fuels and pour in tank cleaners that contain PEA additives.

 

dont know about emissions testing.
If your engine is burning oil, which will harm cats eventually, why not fix that first?

 

Are you getting a Catalyst code?

 

No but the cat honeycomb could be getting clogged slowly from the oil burning, right now put a bottle of Cataclean in the tank