Welcome to Washington state! The emission center will likely not do a tailpipe sniff test. They will just plug into your car's computer and check for emission codes. If you have the o2 sensor delete and no check engine you should be fine. If you fail, no harm. We have a law that only requires you to spend $150 (I think that's the right $) in order to try to pass emissions. Then You get a waiver. Ask the test center for the list of approved emission shops. Call the shops and ask them what you should do. After talking to a few shops you will know who you should take your car to. They likely won't be able to do much of anything for $150 and you will be on your way. Hope this helps.