Bad Air/ Fuel mixture sensor warning for ALL Yaris owners

[eric81]

I highly advise that anyone who owns a Yaris and wants to replace the exhaust header, please read this. Anyone who has already replaced their exhaust header can verify. The factory A/F mixture sensor that is "screwed" into the manifold by the factory is cross threaded, and therefore won't come out. I actually broke mine in half trying to get it out. So, I bought an aftermarket eBay brand A/F sensor on eBay (duh) for a "great" price, and it turns out it almost cost me a new engine. I thought the power was starting to slide a little bit, especially for having a CAI, Megan header, and 3A racing muffler (not really a muffler, as it doesn't muffle or restrict air in any way at all). After I replaced the header, the check engine light wouldn't turn off, and I was running rich all the time, so I forked over the cash to NST (great prices and products... highly recommended) and they shipped me a replacement A/F sensor, and the light went out right away. What I hadn't realized was the damage caused to my engine in that 500 miles I drove with the car running so rich. I just pulled the plugs to check them, and they were burnt to a crisp. I bought replacement ones for about $30 for the set of 4 (yes, I stuck with Iridium's) and set the gap to 44, and started the car. Black and grey smoke came flying out. I also bought some piston, ring, and valve cleaner that I will be using the next time I fill up. My neighbor swears by it, so we will see. Anyways, from my understanding, one or two more thousand miles and I would have just cooked the engine right off. Please plan to buy a new A/F sensor when you buy a new header. And check the plugs soon after the replacement, just to make sure. Drive on!