Ok so after I finally got everything on the cel comes back. The thing is it only comes on when I stop at a red light. I am on the middle restricter plate now. So I am trying to figure out if I should try the smallest next or the largest . I am think the back pressure when coming to a stop is the problem . Any feedback would be appreciated.

 

I had the CEL too because of my test pipe. I used a O2 Space from Vibrant (I think it the same as AMS). I used the larger ring (there were included in the package) and my CEL is gone.

Did you try this one?

 

My CEL comes on even with the spacer. Longest it stayed off would be probably 3months. I have a hi flow cat too...Sucks. I'm using the smallest pill.

 

depends on which code you're throwing. if it's a catalyst efficiency code, you need the smaller opening. if you throw the 02 sensor code, you need the larger opening

 

do you have tuning software? i have accesstuner race and you can modify the map settings like turning off the rear 02 sensor... maybe have ams send u a modified version of your map with that done?

 

I have a code reader let me find out which one it is throwing. Thanks for the info my mind was set on the 0420 code but I was not even thinking about the cat eff code. Very helpful.

It is just weird that it works fine while under throttle and when I start it up but when I come to my first stop it pops on. I will post my findings.

 

P0420 is the cat efficiency code I believe. maybe P0401? or is that a lean/rich condition?

Spending too much time with Fords P0401 is a EGR flow code.

 

OK so I swapped out the middle restrictor for the smallest one and the CEL has not returned I hope I am not giving myself bad luck by posting this but I will see how long it lasts.

 

Keep me posted I also have P0420 with my TP and would love to get rid of my CEL.