After doing countless hours of searching I finally decided to post my first thread.
I have a 02 Envoy and in April my CAT got plugged @ 85,000 miles and I had it replaced with an aftermarket one. However now I'm getting code P0420 wich leads me to beleive that my CAT is getting plugged again..
With that said and before I start waisting more money does anyone have any idea what is causing the CAT to get plugged.
I use regular gasoline rated 87
I've changed the spark plugs to Iridium AC Delcos
I've changed both oxygen sensors
I would think that you are either running rich or else ignition is not lighting all the fuel as it should. If you are having misfires you should/would get codes for that normally. So I lean more towards rich condition. Rich can be caused by a number of things. One that comes to mind is malfunctioning O2 sensor, which causes the computer to make the wrong choices regarding fuel delivery amounts. Another thing, have you changed to a "colder" thermostat or messed with the ECM? Run T-stat that is specified and if you have messed with ECM settings try putting them back to stock maybe.
Getting this code does not necessarily mean your cat. is getting plugged. What type of cat did you have installed? I have heard of some cheap ones called "one pass cats" out there - meaning they are good enough to allow the vehicle to pass an emission test one time.
Welcome aboard. You need to go out to the introductions page and let us know a bit about you and your ride. Oh yea I forgot to mention "We like pictures". You will find the experience on this forum enlightening. The rules of this forum pretty much say it all but when you join other discussions it gives us a chance to also share your experience modding or turning a wrench. Sounds like you might be soaking money into your vehicle that is not necessary trying to find a cure. Not all codes point to a specific problem as you can see. Once again welcome aboard.
There are a lot of aftermarket cats and/or O2 sensors that, unfortunately, will fail after some time; they don't last as long as the OEM's do :no:
Other than that, you should check your fuel trims to see if the truck is running rich; which will cause the cat to fail when unburned fuel heats up on the cat, causing it to melt.
DO a search on cat's; another member wrote out a really good post on the effects of a rich condition or misfire on the catalyst (I forget who, but remember reading it)
Try replacing your O2 sensor First. Also if its a Hi-flow cat, You will probably get that code anyway. There are simulators on the market for the after cat O2 sensor that will simulate a proper working cat. I dont know about the trailvoys though.
Check the connection on your post cat O2 sensor... The GM tech working on my car broke the connector and caused a code indicating the passenger side cat (non-TB) was bad... GM replaced the cat at their cost because of the emissions warranty and a week later the code popped up again... :weird:
I crawled under the car and found the connector pack for the rearward O2 sensor broken, luckily on the O2 side... I had a spare sensor laying around as I had changed the fronts previously and never had the code pop up again after replacing the one with the bad connector...
I have never messed with the thermostat but I'm starting to think that I need to replace it as the temperature keeps falling below the 210 mark and ocassionally it will pass it but not by that much. As for the O2 Sensors I don't see how they would be bad since I just replaced them. I will check the connections this weekend.
The CAT that I last bought was beleived to be good quality and brand. I forget the name of the company but all they do is direct fit CATs. I will post the name when I get it.
I'm starting to think that maybe some oil is leaking into the exhaust system.
Everytime when I first start the car I get the Change Oil light on for the first 30seconds and then it goes off. It never used to do that and it wasn't that long that I changed the oil???
Bonezs the rest of the info you wanted is here because your pm box was full. I took off the vin#s but this is your info.
VEHICLE BUILD
Merchandising Model : TT15506 -2002 ENVOY 4WD (4-DOOR)
Gross Vehicle Weight Rating : 2611 kg (5757 lb) Order Number : DFHK7X
Build Date : 06/08/2001 Build Plant : 12206
OPTION CODES
AJ1 - DEEP TINTED GLASS AJ7 - DRIVER/PASS FRT & SIDE AIR BAGS
AM9 - REAR SPLIT FOLDING SEAT AP9 - CONVENIENCE NET
AR9 - DELUXE FRONT BUCKET SEATS AU0 - REMOTE KEYLESS ENTRY SYSTEM
AXP - MPV VIN IDENTIFICATION BVE - RUNNING BOARDS
B30 - WHEELHOUSING & FLR CARPETING B32 - FRONT COLOR-KEYED FLOOR MATS
B33 - REAR COLOR-KEYED FLOOR MATS CJ3 - DUAL ZONE HVAC
C49 - ELECTRIC REAR WINDOW DEFOGGER C5N - GVW RATING - 5,750 LBS
DAY - ASSEMBLY PLANT MORAINE, OHIO DF5 - LIGHT-SENSITIVE ISRV MIRROR
DK2 - POWER, HEATED OSRV MIRRORS DK7 - CUSTOM INTERIOR ROOF CONSOLE
EVA - EVAP EMISSION REQUIREMENT FE9 - 50-STATE LOW EMISSION VEHICLE
GU6 - REAR AXLE - 3.42 RATIO JF8 - 4-WHEEL POWER DISC BRAKES
KG4 - 150 AMP GENERATOR K34 - ELECTRONIC SPEED CONTROL
LL8 - VORTEC 4200 INLINE 6 CYL ENGINE M30 - 4-SPD AUTO TRANS W/ OVERDRIVE AND ELECTRONIC CONTROL
NF7 - FEDERAL EMISSION SYSTEM NP5 - LEATHER WRAPPED STEERING WHL
N40 - POWER STEERING N75 - CREDIT FOR POLISHED ALUMINUM WHEELS NOT INCL IN PKGS 1SD,1SJ
N79 - STEEL WHEEL FULL SIZE SPARE QTM - P245/65R17 ALS BW TIRES
RYJ - RETRACTABLE CARGO AREA COVER SLM - STOCK ORDERS
TB4 - LIFTGATE/LIFTGLASS BODY T61 - DAYTIME RUNNING LAMPS
T96 - FRONT FOG LAMPS T98 - VIN IDENTIFICATION NUMBER
UA6 - THEFT DETERRENT SYSTEM UE1 - ONSTAR COMMUNICATIONS SYSTEM INCL 1 YR SAFE & SOUND PLAN
UG1 - HOMELINK/TRIP COMPUTER UP0 - ETR AM/FM STEREO, CD/CASSETTE WITH THEFT LOCK, AUTO TONE CONTROL,SEEK/SCAN, AND CLOCK (REPLACES STD/OPT PKG RADIO)
U84 - SIDE WINDOW ANTENNA VP6 - NOISE CONTROL
VXS - COMPLETE VEHICLE LABEL V40 - POWER PASSENGER SEAT
V73 - STATEMENT OF CERT. U.S. YC5 - SLE DECOR
YD3 - BASE EQUIP FOR SCH GVW PLATE YD5 - FRONT SPRING - BASE EQUIPMENT
YD6 - REAR SPRING - BASE EQUIPMENT ZW7 - PREMIUM SMOOTH RIDE SUSPENSION
ZY1 - SOLID PAINT Z88 - GMC TRUCK NAMEPLATE
1SB - SLE ENHANCED PACKAGE (SB) * AM/FM STEREO CASSETTE/CD * CONTENT THEFT ALARM * POWER PASSENGER SEAT 41U - 41 ONYX BLACK
6DA - COMP FRT LH COMPUTER SEL SUSP 7DA - COMP FRT RH COMPUTER SEL SUSP
8DM - COMP RR LH COMPUTER SEL SUSP 9DL - COMP RR RH COMPUTER SEL SUSP
92H - DARK PEWTER 92I - DARK PEWTER INTERIOR TRIM
Vehicle Component
Component Code : 10 - ENGINE ASSEMBLY
Source Plant : V - CPC FLINT, MICHIGAN
Part/Num Broadcast : MN2 Traceability : 106060343
Date Scanned : 06/08/2001 Time Scanned : 00.49.00 Scan Station : 01
Component Code : 35 - STEERING COLUMN - SIR SYSTEM
Source Plant : S - SAGINAW DIVISION SAGINAW,MI
Part/Num Broadcast : USP Traceability : 101711511
Date Scanned : 06/08/2001 Time Scanned : 01.00.00 Scan Station : 05
Component Code : 60 - TRANSFER CASE (4 WHEEL DRIVE)
Source Plant : N
Part/Num Broadcast : PH Traceability : 0AH979680
Date Scanned : 06/08/2001 Time Scanned : 00.57.00 Scan Station : 03
Component Code : 61 - TRANSMISSION
Source Plant : Y - HYDRAMATIC TOLEDO, OHIO
Part/Num Broadcast : 2TDD Traceability : 31135107
Date Scanned : 06/08/2001 Time Scanned : 00.52.00 Scan Station : 02
Component Code : 63 - FRONT AXLE/FRONT CRADLE WITH FRONT HUB ASSEMBLIES
Source Plant : G
Part/Num Broadcast : UP1 Traceability : 7CK012
Date Scanned : 06/08/2001 Time Scanned : 01.00.00 Scan Station : 12
Component Code : 65 - REAR AXLE ASSEMBLY
Source Plant : C - SAGINAW BUFFALO, NEW YORK
Part/Num Broadcast : TF2 Traceability : 150183600
Date Scanned : 06/08/2001 Time Scanned : 01.11.00 Scan Station : 11
Component Code : 92 - BRAKE PRESSURE MODULATOR VALVE ASSEMBLY
Source Plant : K - KELSEY-HAYES JASPER, INDIANA
Part/Num Broadcast : 3077 Traceability : 00057829
Date Scanned : 06/08/2001 Time Scanned : 02.04.00 Scan Station : 15
Component Code : AB - IR-MODULE ASM-INFLATOR
Source Plant : Q - RIMIR MATAMORS MEXICO
Part/Num Broadcast : 0888 Traceability : 5BZT4L4
Date Scanned : 06/08/2001 Time Scanned : 05.42.00 Scan Station : 06
Component Code : AD - IR-SENSOR-FORWARD
Source Plant : X - DELCO ELECTRONICS SINGAPORE
Part/Num Broadcast : 5645 Traceability : A1KXT
Date Scanned : 06/08/2001 Time Scanned : 03.06.00 Scan Station : 14
Component Code : AL - IR-MODULE ASM-I/P
Source Plant : M - MORTON-THIOKOL
Part/Num Broadcast : 1214 Traceability : 7VAHL47
Date Scanned : 06/08/2001 Time Scanned : 00.53.00 Scan Station : 04
Component Code : AS - SENSING DIAGNOSTIC MODULE
Source Plant : K - DELCO ELECTRONICS KOKOMO,IN
Part/Num Broadcast : 0860 Traceability : 211551W05
Date Scanned : 06/08/2001 Time Scanned : 01.35.00 Scan Station : 09
Component Code : AU - LEFT SIDE IMPACT SENSING MODULE
Source Plant : X - DELCO ELECTRONICS SINGAPORE
Part/Num Broadcast : 6623 Traceability : 0K8DV
Date Scanned : 06/08/2001 Time Scanned : 05.19.00 Scan Station : 08
Component Code : CB - SEQ NUM (FLEX) BODY ASM
Source Plant : N/A
Part/Num Broadcast : 1ZZ Traceability : 0970385
Date Scanned : 06/02/2001 Time Scanned : 02.03.00 Scan Station : N/A
Component Code : CF - SEQ NUM (FLEX) PAINT PROCESS
Source Plant : N/A
Part/Num Broadcast : 1WS Traceability : 7073347
Date Scanned : 06/06/2001 Time Scanned : 11.55.00 Scan Station : N/A
Component Code : CM - SEQ NUM (FLEX) GEN ASM
Source Plant : N/A
Part/Num Broadcast : 1PB Traceability : 7062225
Date Scanned : 06/07/2001 Time Scanned : 18.47.00 Scan Station : N/A
Component Code : CP - SEQ NUM (FLEX) GEN ASM
Source Plant : N/A
Part/Num Broadcast : 1GA Traceability : 7070971
Date Scanned : 06/07/2001 Time Scanned : 20.43.00 Scan Station : N/A
IN-SERVICE INFORMATION
In-Service Information Not On file
DELIVERY INFORMATION
Delivery Date : 12/06/2001 Delivery Type : 010 - RETAIL/INDIVIDUAL Delivered Odometer : 56 miles
Delivering Dealer : HOWARD BUICK-PONTIAC-GMC
364 W GRAND AVE
ELMHURST , IL 60126-1137
(630) 832-9500
Delivery Selling Source : 48 - GMC TRUCK
Delivery Site Code : 14126
Business Associate Code : 116053
INVOICE INFORMATION
Invoice Date : 06/08/2001
Site Address : JOE MITCHELL BUICK-GMC TRUCK, INC.
801 E RAND RD
MOUNT PROSPECT , IL 60056-2595
(847) 394-2200 Selling Source : 48 - GMC TRUCK
Site Code : 26681
Business Associate Code : 118526
SHIP-TO INFORMATION
Ship-To Date : N/A
Site Address : JOE MITCHELL BUICK-GMC TRUCK, INC.
801 E RAND RD
MOUNT PROSPECT , IL 60056-2595
(847) 394-2200 Selling Source : 48 - GMC TRUCK
Site Code : 26681
Business Associate Code : 118526
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