My fiance’s 2001 Toyota Celica GT had a check engine light on for faulty o2 sensors for a long time and we just now got around to replacing them. Car was running perfectly fine on old sensors, good gas mileage and everything, we just wanted to get rid of the check engine light in hopes to sell the car.
So I bought the matching upstream and downstream O2 sensors from Amazon (Denso brand) and went to install them and didn’t have any problems doing so.
Then when I thought the job was done I turned on the car to find it sputtering, backfiring, and barely able to keep staying on without me throttling it. I have heard that some cars need some time to adjust to the new O2 sensors so I keep restarting the engine, idling it, throttling it, driving around in circles slowly, but nothing is working.
After a half hour of trying to get it working by doing this I decide to switch back to the old O2 sensors temporarily thinking I just got a bad new O2 sensor from the manufacturer.
Only thing is after switch the old ones back on the car still sputtered like crazy for a while until it seemed to be running fine. We drove the car about 2 miles reaching up to 60 mph and had no problems. Fast forward 2 hours later and the same problems are back and the car is barely running.
What in the world is going on!