This has been a long problem I have been working on, it started around 160K I had a long road trip to Ohio and back to VA for X-Mass last year. The car did wonderful until 20 miles from home. The car started misfiring and I got an error on the dash of electrical problem. I pulled over checked all the fluids restarted and all was well. Got home with no problems. A week later I was headed down the road but when I got to a hill it felt like I was losing power fast and then got the electrical warning as well as rear brake sensor, (I know I do need a break job on rear). At home the car idled fine but had the smell of raw gas from exhaust.
Had my indy look at it as I normally do my own work but I didn't have an OBD scanner at the time. It showed bad O2 sensor and multiple misfires. I went ahead as I was at 160K now and had all plugs replaced, boots, all 4 O2 sensors (with Bosh) and fluids changed. Did not replace ignition coils. After this car ran beautiful again for about 6k.
At around 6k later got electrical problem warning and sometimes felt misfire. I bought a scanner and checked and reported Right front O2 sensor and misfire on 2,3,8. The gas smell was back as well. This was the start of my long repairs.
First I replaced Boots on 2,3,8 --- no change
Replaced all plugs - (indy had used platinum, I replaced with non platinum)
Also replaced ignition coils on 2,3,8
Car is even worst now reporting multiple misfires, O2 sensor, Misfires on 2,3,8,5 and when I try to drive it the car has no power, idles well but once I start driving and get to 25MPH everything goes to hell and the misfires start and I can’t go any faster even at high rpm. It actually now feels like the trany is in the safe/get home mode.
Any ideas? What do I test next, I have not replaced the O2 sensor just because I can't see one sensor doing all this. Some one suggested a fuel pressure or supply issue but I don't know how to test this or what to replace next.

My first suspicion would be a bad mass airflow sensor.

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__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

Sorry forgot to mention I also replaced the MAF. This did nothing to help the problem.

I am going to guess the catalytic converter is bad and/or the cam position sensor is damaged.


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__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

I will agree with that, for some reason it skipped my mind and last night I got under the car as it was running. The front passenger side exhaust to the cat was glowing red hot at the neck as it goes into the cat. After running I tried tapping it with a rubber mallet but don’t hear any raddle like I am used to in a bad cat. Also can I just replace this one cat or to I have to do all 4 or both front ones? Is there a way to test the cam sensor too?