Limp mode after going catless

Cashcam

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Please read and I appreciate any feedback whatsoever thank you.

So I got a completely clogged cat, so decided to go catless as it was the fastest cheapest option. I got 1 solid drive out of it couple hours and the next day it started throwing codes and went into limp mode.

So far I’ve replaced fuel filter, maf sensor, coil pack, pcv hoses, 02 sensors & I’ve cleaned fuel injectors, throttle body, Cai filter.

Right now it will run perfectly fine if I reset the battery but after about 15 minutes of run time idle or driving it will go back into limp mode. It’s very sever as well I can have the throttle to the floor and barley get above 10-15 mph

Just got the codes read again and my main code is bank 2 sensor 1 02 sensor causing rough idle & misfires. It is sitting as of now with a stock tune and I do plan on getting one in the next month or two. A friend of mine told me to just put on high flow cats and see if it fixes it but is there anything else I can try first ?
 

lwarrior1016

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You’ve got a fault for bank 2 sensor 1?

That’s an upstream sensor and that controls fueling. You need to get that fixed. Make sure you didn’t damage any wires when you took the mid pipe down to remove the cats. Or with a clogged cat, it’s possible that sensor got burnt out.
 

Cashcam

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Replaced both upstream 02 sensors after I did the cat delete. could it just be a faulty o2 sensor I do know that can happen even with brand new ones.
 

Midlife Crises

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Are you saying your car is tuned for running catalytic converters and you removed them without altering the tune? I would say that is the rout of your problem. Regardless of the codes registered, adjustments to the vehicles tune would be required to omit the Cats.
 

07 Boss

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How exactly did you go catless? Have you checked for any exhaust leaks? The smallest of leaks can give our sensors issues.

On a sidenote, I went with headers and an off road H pipe and never had any tune issues or misfires except the smog codes for the rear sensors.
 

Cashcam

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Are you saying your car is tuned for running catalytic converters and you removed them without altering the tune? I would say that is the rout of your problem. Regardless of the codes registered, adjustments to the vehicles tune would be required to omit the Cats.
It’s a stock tune from the factory. So yea it’s tuned to run with cats anyway to get by without a tune for the time being?
 

Cashcam

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How exactly did you go catless? Have you checked for any exhaust leaks? The smallest of leaks can give our sensors issues.

On a sidenote, I went with headers and an off road H pipe and never had any tune issues or misfires except the smog codes for the rear sensors.
Knocked the inside of the cats out put the mid pipe back on. Did you run with a stock tune or did you have a tune done to the car?
 

whitmanink

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when i got my gt wrecked from co-part, the car came with no cats,,, funny thing is no CEL was ever on or shoed up as a temp code on my scanner,,
well fast forward a moth or so later, i got a CAI and a SCT tune that came with the tunner,, still no CEL,, than after a lito tune ,, i told him im catless and obviously he tuned the o2 out,,,, im wondering why i never sent a code ?
 

07 Boss

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Knocked the inside of the cats out put the mid pipe back on. Did you run with a stock tune or did you have a tune done to the car?


Wasn't a stock tune but I ran the same tune with factory exhaust and the off road header set up. Never an issue except for the smog stuff. Engine ran fine for years until I threw a blower on her.
 

Midlife Crises

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I installed Kooks long tubes, a cat less X pipe and magnapack cat back on my 2010 GT. Throttle response was terrible after the engine warmed up. Flat spots and hesitation. Don’t remember the codes but it threw several. When the traction control would collide with the hesitation the some crazy bucking would result and turn on the wrench and limp mode. A few days later the SCT tuner and cold air intake showed up in the mail. After installing the JLT intake and the first of three tunes in the X3 all the evil went away.
Funny, in those days you could get tunes with or without the rear O2 sensors active. I had 87 octane w/o2 active, 93 octane w/o2 active and 93 octane w/o2 turned off.
 

86GT351

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You stated you knocked the cats out. Are you 15% that you got all of it out? If you have a piece wedged in there creating a blockage it can cause an issue
 

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