This has worked but isn't gauranteed.

Don't drop your car off. Fill up with super and and an octane boost wouldn't hurt, I use BG44k which is like methamphetamines in octane form.

Keep the car running for at leat 1 hour. So if there's a line and your waiting, let it run at idle the whole time.

It worked for me in one of my old cars. I was double the output of Carbon Monoxide, and then I tried this method and passed, saving me 550$ which is what the cost of replacing whatever in order for me to pass.

Good Luck