Is it possible that adding MH can throw a cat. conv. code?

Anything else is would do negative wise, would also be helpful. Please don't tell me about ruining rubber, as gasline antifreeze IS Methyl Hydrate. Thanks. And yes, I added it and failed Aircare with a 0420 I think, which was the cat.

I then had a new cat put in. Turns out the old one was previously hollowed out. So that alone would account for the code. I just HOPE the code doesn't come back before I re-test later today. Or I'm screwed.

 

Dont think it was the MH, I would bet its a bad o2 sensor

 

I hope you're right. As I also had a new sensor put in at the same time. And the second sensor was also done about 3 months ago. I'm just freakin' out that the code will come back for my Aircare today. Then I'd be stuck with day insurance only, as I've already my 3 month "fail" insurance. And seems the money I've spent so far will mean screw all, as my mech. is not a certified Aircare mech.

 

There is also a hard code stored in the computer, usually takes 75-100 miles to clear that one

 

Ok, I JUST went through Aircare, again. It failed again!.........same code as before, P0420. The cat again???? But I just had a new cat put in, and both sensors there are also new. Ughhh. Can you or anyone help me with this? (could it be because I still have some Methyl Hydrate mixed with the gas?)

 

even if you dont have a check engine light.once erased it takes about 100 miles of driving to clear it from the computer