Okay as title says there are problems. I normally would research all this but can't really focus well with the reports we are getting on my wife's Dad. We are down to 2 cars and mine needs repairs so if she goes to her father and mother the kids and I could have car issues, so I appreciate anyone who can connect the dots on probably related codes and hopefully I can repair it without more parts.
To issues:Couple months ago the cat stopped up in the 2000 SSEI.
Still was able to drive at part throttle, eventually the check engine light for O2 sensors would go on and off. Finally was able to replace cat(guy said the pellets were gone in my factory cat so wonder if stopped up a muffler because check engine light stayed on even with new cat).

Codes:P0137
PO300
PO141
P1404
P0404

What I have done. Other than new cat (did not reset code wonder if that is it?) anyhow other than new cat I have pulled the EGR valve off and it is clean and not binding(do not know how to check electrically) started to pull o2 sensor under the EGR but decided to stop and ask you guys before I get to far out.
Thanks in advance for any help. Things are kind of hectic so may be tough to respond right back but I will. Thank you

_________________
John

North Carolina:
2000 SSEI (FINALLY something nice! Thank you Lord!)
1970 Buick GS 455 STOCK 510ft lbs of torque at 2800rpm's! (in works)
1972 Buick GS Stage 1 (total basket case)
1960 Buick Electra 225 convertible (when "225" stood for 225" long)
1976 & 77 Jeep (Just Empty Every Pocket!) Wagoneer 360 AMC

The codes all relate to the EGR and the rear oxygen sensor. I'd suggest getting a good used EGR valve from Harofreak00, and replacing the O2 sensor.

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*Gone, but not forgotten* - Black 2000 SSEi, HIR Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, 180 degree thermostat, HS 1.9 rockers, LSx yellow springs, Intense FWI, PCM, shift kit, push rods, and 3.4 Pulley. ZZP Power Log.

really sorry about your wife's father. Hope there is good news soon about him. - BC

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In Memory of Brad - 1/21/1977 .. 10/23/2013 ...... Aaron - 1977 .. 2017 .....
2017 Hyundai Santa Fe Sport ..... 1992 Bonneville SSE 1SB 170 HP L27 4T60E retired/sold to MattStrike ..... 2005 Bonneville SE 1SC 205 HP L36 4T65E - retired/salvage yard ..... PBCF user 2321

Thanks for the kind words for my wife's Dad.He is out of the ICU so good news there but currently can't walk and will have to go into assisted living hopefully temporarily until they get the issues resolved.

On the car, I found a new EGR on Amazon for $65 including shipping but didn't want to order that if the O2 sensor being replaced might cure the EGR code. I removed the EGR and it was clean as a whistle and moving freely. Did not see any broken vacuum lines but did see a pile of grease on the lower passenger firewall so guess I will be needing a CV boot or something too when I have time to get it on the ramps.

Okay I have physical therapy but thank you again for both the advice and well wishes.

_________________
John

North Carolina:
2000 SSEI (FINALLY something nice! Thank you Lord!)
1970 Buick GS 455 STOCK 510ft lbs of torque at 2800rpm's! (in works)
1972 Buick GS Stage 1 (total basket case)
1960 Buick Electra 225 convertible (when "225" stood for 225" long)
1976 & 77 Jeep (Just Empty Every Pocket!) Wagoneer 360 AMC

There have been a couple of cases of the O2 setting an EGR code, but I believe that it was the front O2 and it was a code for EGR flow, not position error. If you want, try the O2 first and see if it helps.

_________________
*Gone, but not forgotten* - Black 2000 SSEi, HIR Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, 180 degree thermostat, HS 1.9 rockers, LSx yellow springs, Intense FWI, PCM, shift kit, push rods, and 3.4 Pulley. ZZP Power Log.

I agree, clean the EGR and replace the primary O2 sensor then clear the codes.. see what pops on if anything at that point.

_________________
Shane "RedZMonte"
2004 Z16 Z06: Virgin
2000 SSEi: Kenwood DDX512, 3.25" MPS, ZZP DP, PLog, Puck Mount, NGK TR7's, DHP Tuned
1995 Monte Z34: T04e "60" turbo, 42.5# injectors, Borla Catback, OBDII swap, DHP Tuned, Much more...

This initially started when my cat got stopped up. Didn't have the money for the cat so had to drive it around part throttle and it drove fine. At that point there was no check engine light after a couple months the check engine light would go on and off until it finally stayed on permanently . I just figured the cat had gotten more stopped up causing the light to stay on but when my muffler guy removed the factory cat he said the cat pellets were all but gone (a friend and I had previously heated the car up on ramps and beat on the cat with a large rubber mallet while keeping the RPMs up so guess we blew most of the pellets out).

I noticed I could get full throttle once again before I had the Magnaflow cat installed and all performance felt fine but with the light still on I figured there was still an obstruction so installed the new cat. Light did not go off after replacement but I also did not reset the code. From that point with the new cat and light still on I had it scanned and got the codes above. Maybe I should reset the computer first? Like I said the EGR looked fine and it's parts moved freely when manually engaged. I have not been able to drive the car except to my physical therapy but it seems the gas mileage is way off.

So how is this for a plan?
1. Reset the computer
2. Rescan
3. If O2 code and EGR are still on replace the O2 first and see where I am after that code and light wise

Really appreciate ya'll helping here, got allot on our plate and I am fighting every day to keep the family cars on the road along with the personal issues.Gets a little much sometimes but is nice to have friends to reduce some of my guess work, so Thanks again

_________________
John

North Carolina:
2000 SSEI (FINALLY something nice! Thank you Lord!)
1970 Buick GS 455 STOCK 510ft lbs of torque at 2800rpm's! (in works)
1972 Buick GS Stage 1 (total basket case)
1960 Buick Electra 225 convertible (when "225" stood for 225" long)
1976 & 77 Jeep (Just Empty Every Pocket!) Wagoneer 360 AMC

Keep in mind that your codes are for the rear O2 sensor. If the codes return, you'll have to replace both sensors for a complete test to get rid of the light.

_________________
*Gone, but not forgotten* - Black 2000 SSEi, HIR Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, 180 degree thermostat, HS 1.9 rockers, LSx yellow springs, Intense FWI, PCM, shift kit, push rods, and 3.4 Pulley. ZZP Power Log.