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p0420 trouble code eliminator?

S

spdjnky_42

New CEG'er
Joined
Jan 2, 2011
Messages
11
Hey guys new here. Usually over at the Mustang forums. I bought a 99 Mercury Mystake with a 2.5L v6. Nice car but it had 5 codes. I fixed the others nothing major but once I fixed them I got code p0420. I am guessing that to be a bad cat or an ECM flash issue. It had some codes they were vacuum leak and bad 02 on bank one. I can almost get everything reset then the CEL comes back. I have only seen 2 02 sensors on this car but I am assuming there is a post cat 02? A new cat is twice what I paid for this car just would like to get it legal and drive it til she dies. I found the MIL elims can someone tell me how to set them up on a 99 2.5l?
 
Thanks I read that link already. Still no link I read another thread that said nautilus is not a good place to buy those?
 
More than anything I am confused on how many I need for a 2.5L and where they go. I thought they go on the down stream sensor but I havent seen any on this car only the uppers.
 
I would recommend O2 extenders before MIL eliminators. They accomplish the same thing, but the extenders are cheaper and more reliable.

The extenders or MIL,s are installed on the o2 sensors located downstream of the exhaust manifolds. One is just in front of the catalytic converter, the other is on the y pipe near the radiator.
 
With that code you dont want to mess with the ones pre-cat(before). These are the O2 sensors in the exhaust maifold, one is right above/around the oil filter, the other is on the backside of the engine under the coilpack area. Really hard to see. I had the same code. The ones you want to put the MIL eliminators on are Post-cat(after). Those are the easiest to see, one is in the ypipe and the other right off the manifold in the front of the engine.
 
I have had luck on two cars my 2000 svt and my wifes 99 mystique just replacing the upper O2s. This got rid of the codes and I think I have over 30 or 40k on the new sensors with no codes. I have never replaced the lower ones. My theory on why this is working is the computer is looking for the second O2s to lag behind the first O2s in a certain manner when you replace the upper ones the new ones respond much faster then the old ones causing the right difference. You could also do the MIL eliminator on the lower ones making the right difference in readings but maybe your uppers need replacing anyways.
 
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