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I have a 2008 ford 4.6L mustang I bought recently. I got it off auction so I don't know anything about the vehicles mod history.

From what I can tell, the owner put on Borla exhausts, cams, and a tune. The owner left his original SCT XCalibrator 2 tune installer with 2 tunes and 1 stock tune on it.

I need to pass I/M readiness, but my Cat, O2, and O2 heater sensors are incomplete. Ive tried all the drive cycles I can find, and have put on over 150 miles trying to get them to complete.

I wonder if the tune has the rear O2 sensors turned off to keep the MIL from turning on. I'm also wondering if the high flow muffler delete Borla exhaust’s will affect the completion of the sensors.

Ive read in other forums that people go back to stock exhausts and stock tune and have the issue fixed that way. But I don't have the luxury of having the stock exhausts with me. Ive read about other people putting plates in their exhausts to restrict airflow and allow the CAT to heat up to the correct activation temp.

If you guys have any solutions or any ideas, let me know! Ive been trying to fix this issue for the past month, and I need to pass inspection asap in 2 weeks. Any help is greatly appreciated 🙏
 

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I have a 2008 ford 4.6L mustang I bought recently. I got it off auction so I don't know anything about the vehicles mod history.

From what I can tell, the owner put on Borla exhausts, cams, and a tune. The owner left his original SCT XCalibrator 2 tune installer with 2 tunes and 1 stock tune on it.

I need to pass I/M readiness, but my Cat, O2, and O2 heater sensors are incomplete. Ive tried all the drive cycles I can find, and have put on over 150 miles trying to get them to complete.

I wonder if the tune has the rear O2 sensors turned off to keep the MIL from turning on. I'm also wondering if the high flow muffler delete Borla exhaust’s will affect the completion of the sensors.

Ive read in other forums that people go back to stock exhausts and stock tune and have the issue fixed that way. But I don't have the luxury of having the stock exhausts with me. Ive read about other people putting plates in their exhausts to restrict airflow and allow the CAT to heat up to the correct activation temp.

If you guys have any solutions or any ideas, let me know! Ive been trying to fix this issue for the past month, and I need to pass inspection asap in 2 weeks. Any help is greatly appreciated 🙏
IMHO, I think you are on track....best to call the tuner company and see if they have any info, if not, then it's going to start getting fun.
 

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...From what I can tell, the owner put on Borla exhausts, cams, and a tune. The owner left his original SCT XCalibrator 2 tune installer with 2 tunes and 1 stock tune on it. ....
I wonder if the tune has the rear O2 sensors turned off to keep the MIL from turning on. I'm also wondering if the high flow muffler delete Borla exhaust’s will affect the completion of the sensors.
Most likely it is the tune. It was very common to turn off the rear O2 sensors in most "custom" tunes in the past (less common now that EPA is "cracking down" on this horrible practice, LOL). I don't know exactly why they did it, but the "simple" fix is to turn them back on.

If you know who wrote the tune, they should be able to write you a new one with the rear O2's on. Or if you don't know, I would recommend "Lito" who does remote tuning via e-mail using datalogs for about $150.

The mufflers should not cause this issue, but the cams probably do require a tune, so you can't just put the factory tune back in the car.
 
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I have a 2008 ford 4.6L mustang I bought recently. I got it off auction so I don't know anything about the vehicles mod history.

From what I can tell, the owner put on Borla exhausts, cams, and a tune. The owner left his original SCT XCalibrator 2 tune installer with 2 tunes and 1 stock tune on it.

I need to pass I/M readiness, but my Cat, O2, and O2 heater sensors are incomplete. Ive tried all the drive cycles I can find, and have put on over 150 miles trying to get them to complete.

I wonder if the tune has the rear O2 sensors turned off to keep the MIL from turning on. I'm also wondering if the high flow muffler delete Borla exhaust’s will affect the completion of the sensors.

Ive read in other forums that people go back to stock exhausts and stock tune and have the issue fixed that way. But I don't have the luxury of having the stock exhausts with me. Ive read about other people putting plates in their exhausts to restrict airflow and allow the CAT to heat up to the correct activation temp.

If you guys have any solutions or any ideas, let me know! Ive been trying to fix this issue for the past month, and I need to pass inspection asap in 2 weeks. Any help is greatly appreciated 🙏
Aftermarket exhaust parts of any kind will often cause this situation and it's been very well documented. This thread has several people that went thru hell to get their monitors complete and all of them had one thing in common: aftermarket exhaust parts. There was at least one of the following installed on their cars: headers, H or X pipes, larger diameter pipes, aftermarket or GT500 mufflers, etc. Even just having GT500 mufflers caused this monitor readiness problem.
(239) RESOLVED: O2 monitor and o2 heater incomplete | Ford Mustang Forum (allfordmustangs.com)
The only thing that got their monitors to pass was either returning the car exhaust to stock or temporarily creating more backpressure in the aftermarket exhaust. This coupled with monitoring the cat temps as they were driving to make sure they got hot enough for long enough was the solution.
 

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Aftermarket exhaust parts of any kind will often cause this situation and it's been very well documented. This thread has several people that went thru hell to get their monitors complete and all of them had one thing in common: aftermarket exhaust parts. There was at least one of the following installed on their cars: headers, H or X pipes, larger diameter pipes, aftermarket or GT500 mufflers, etc. Even just having GT500 mufflers caused this monitor readiness problem.
(239) RESOLVED: O2 monitor and o2 heater incomplete | Ford Mustang Forum (allfordmustangs.com)
The only thing that got their monitors to pass was either returning the car exhaust to stock or temporarily creating more backpressure in the aftermarket exhaust. This coupled with monitoring the cat temps as they were driving to make sure they got hot enough for long enough was the solution.
One of the other "Sometimes Works" is to relocate the O2 sensors as close to the rear of the CATS as you can as this is obviously the hottest spot of the exhaust and will most likely heat the O2 sensors the best.
 
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