I think my cat's going bad the car's throwing a P0420 ses code and I know gm had a extended warranty for the cat's on these cars but it was 7 years 100k I made my service advisor at pontiac aware of the issue before 100k so If its a bad cat I hope they will help

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Modded Like a Mother Fu**er and still gets 20+ mpg and runs 14's

What exactly do you need help with? I don't see any questions in your post.

Does this code P0420 which states Catalyst System Low Efficiency point to a bad cat or one or both of the 02 sensors going bad thats the question. Sorry for not wording it better.

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Modded Like a Mother Fu**er and still gets 20+ mpg and runs 14's

to test the cat

1 Meet the conditions for engine warm up. Use the scan tool catalyst data list in order to verify the following:
DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0130, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0171, P0172, P0201-P0206, P0300, P0336, P0341, P0401, P0403, P0404, P0405, P0410, P0412, P0418, P0440, P0442, P0443, P0446, P0449, P0502, P0503, P0506, P0507, P1133, P1134, P1336, P1351, P1352, P1361, P1374, or P1441 are not set.

The engine has been running more than 10 minutes.
The engine coolant temperature (ECT) is above 70°C (158°F) and below 124°C (255°F).
The barometric pressure (BARO) is above 75 kPa.
The vehicle is in Closed Loop.
The intake air temperature (IAT) is above -20°C (-4°F), and is less than +100°C (+212°F).
The battery voltage above 10.7 volts


2 Warm the catalyst.

Fully open the hood.
Transmission is in park (automatic) or neutral (manual).
Set the parking brake.
Press and hold the service brake.
Each time the engine is started the diagnostic can run up to 18 times. After the 10-minute run time and before the diagnostic runs the first time, the engine must run an additional 5 minutes between 1,500-2,500 RPM. Any additional tests on the same key cycle, the engine speed must be between 1,500-2,500 RPM for 1 minute.
To activate the diagnostic, return to idle and put the vehicle in drive (depress the clutch for manual).


3 Test the catalyst.

Transmission is in drive (automatic) or neutral (for manuals with the clutch depressed).
VIN K California Emissions--Within 60 seconds the air fuel ratio will go rich below 14.1 for up to 6 seconds, then may go lean above 15.3 for up to 8 seconds.
VIN K FED Emissions--Within 60 seconds the air fuel ratio will go lean above 15.3 for up to 6 seconds, then may go rich below 14.1 for up to 7 seconds.
VIN 1--Within 60 seconds the air fuel ratio will go rich below 14.1 for up to 7 seconds, then may go lean above 15.3 for up to 9 seconds.
Verify if DTC P0420 has passed or failed this key cycle using the scan tool.

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I'm totally lost there alex how do you start the test cycle's

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Modded Like a Mother Fu**er and still gets 20+ mpg and runs 14's

clear teh codes

makes sure the car is doing this:

The engine has been running more than 10 minutes.
The engine coolant temperature (ECT) is above 70°C (158°F) and below 124°C (255°F).
The barometric pressure (BARO) is above 75 kPa.
The vehicle is in Closed Loop.
The intake air temperature (IAT) is above -20°C (-4°F), and is less than +100°C (+212°F).
The battery voltage above 10.7 volts

the these conditions:

Fully open the hood.
Transmission is in park (automatic) or neutral (manual).
Set the parking brake.
Press and hold the service brake.
Each time the engine is started the diagnostic can run up to 18 times. After the 10-minute run time and before the diagnostic runs the first time, the engine must run an additional 5 minutes between 1,500-2,500 RPM. Any additional tests on the same key cycle, the engine speed must be between 1,500-2,500 RPM for 1 minute.
To activate the diagnostic, return to idle and put the vehicle in drive (depress the clutch for manual).

and then reading the car depending on the vin number you get:

Transmission is in drive (automatic) or neutral (for manuals with the clutch depressed).
VIN K California Emissions--Within 60 seconds the air fuel ratio will go rich below 14.1 for up to 6 seconds, then may go lean above 15.3 for up to 8 seconds.
VIN K FED Emissions--Within 60 seconds the air fuel ratio will go lean above 15.3 for up to 6 seconds, then may go rich below 14.1 for up to 7 seconds.
VIN 1--Within 60 seconds the air fuel ratio will go rich below 14.1 for up to 7 seconds, then may go lean above 15.3 for up to 9 seconds.
Verify if DTC P0420 has passed or failed this key cycle using the scan tool.

so if the vin number code makes the cat pass you know its the o2's or something else
but my money is on the cat

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I changed to permo gas and its not came back and the car was cold when i started it this mornning and was flowing the same ammount of steam from the tail pipes so I dunno. But the car u bend and res are gone in a week or 2

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Modded Like a Mother Fu**er and still gets 20+ mpg and runs 14's

shove a tes pipe through it. dont need it anyways.

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.: ZZP 1.0 : HV3 : P&P L26 HEADS : ER ROCKERS : PLOG/CROSSOVER/REAR PEM : 4 " FWI : ZZP STAGE1 HVTB : 2.5" DP : CAT/RES/UBEND DELETE : 180* : ALT RE-WIRE : OPTIMA :.

Won't the down stream 02 read wrong???

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Modded Like a Mother Fu**er and still gets 20+ mpg and runs 14's

it will read slightly off since there will be more flow but an after market pcm should compensate

also your stock pcm should learn to adjust for the increased power and rear flow

so to save the time and gas disconnect the battery

also i'm sure over the years hundreds have done it successfully and luckily you live in florida one of the most lax states in the country as far as exhaust and vehicle restrictions

so do it if you can get away w/ it

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but the main ? will the ses light be set off?

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Modded Like a Mother Fu**er and still gets 20+ mpg and runs 14's

it may
but again the aftermarket pcm will delete the rear o2 so it won't throw the code

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I guess i'll have to go see L67 swap over in polk county then after i do this so he can tune the car

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Modded Like a Mother Fu**er and still gets 20+ mpg and runs 14's