Those codes are all pointing at a related issue. A/F ratio falling out of range, heater elements within the O2's out of temp range, EGR sensor or exhaust gas temp falling out of range, etc. There is a few areas to consider...
Was any work recently done to the car that may have triggered this? When was the last time you replaced the O2 sensors? Check the O2 connectors and wiring to make sure one of them hasn't contacted the exhaust or melted. Any exhaust leaks especially before the cats? When was the last time you performed an induction service and cleaned the intake, TBs, IAC, etc? The EGR and IACV love to get carbon buildup over the years and can affect flow, similarly can happen to the vac lines to the factory wastegate control solenoid. You mentioned the car felt like it was still running well, so no idle RPM fumbling, hanging, stumbling, etc? Are you running an aftermarket boost control solenoid or OEM? Sorry for the load of questions, but need a bit more to go off of to help point you in the right direction.
Even though the vehicle has considerable low mileage, it's still 30 years old. If it's kept in a garage it tends to handle the elements better than sitting out in the external environmental conditions and will need more routine maintenance and care regardless if it's being driven or not. (i.e. 60K / 120k maint w/ timing belt)
By
protoj ·
Never
A list of things you should never do.
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Never eat at a place called Mom's.
Never play cards with a man named Doc.
Never go to a doctor whose office plants have died.
Never offend people with style when you can offend them with substance.
Never share a foxhole with someone who is braver than you are.
Never argue with a woman when she's tired.
Never argue with a woman when she's rested.
Never stand between a fire hydrant and a dog.
Never go to bed mad. Stay up and fight!
Never decide to buy anything while listening to the salesman.
Never argue with a fool. People may not be able to tell the difference.
Never use a preposition to end a sentence with.
Never argue with a man who buys ink by the gallon.
Never insult an alligator until you have crossed the river.
Never say "Oops" in an operating room.
Never try to out-stubborn a cat.
Never characterize the importance of a statement in advance.
Never eat prunes when you're hungry.
Never say, "Sorry, we don't have what you're looking for." Always say, "I just sold the last one the other day."
Never use one word when twelve will suffice.
Never be the first to do anything.
Never let go of what you have unless you have hold of something else.
Never put off until tomorrow what you can put off until the day after tomorrow.