Hey guys,

I have a friend who has a 1997 Mercury Cougar with the 3.8 V6. She told me that a mechanic told her that her car needs Cats and all 4 O2 sensors. The check engine light is on.

Now here is the weird part. She took it for emissions today and it passed. I am beginning to question the diagnosis and plan on scanning it myself when I get by the car next time.

My question is this. If that mechanic was correct, is there any possible way it could still pass emissions and have that many problems, or should I be looking for another cause.