I have a 2006 Chevy Malibu 125,000 miles that was running sluggish, noisy like needed oil (checked didn’t) and check engine light was on. Took it to a repair shop and told needed an oil change, car still ran sluggish, told to drive it a day or so. Two days later, car wouldn’t go over 50 mph, took it back and told needed air filter and mass air flow cleaned. After they did that, they told me the Catalytic converter needed replaced however they don’t do that work. Within a week car would not run so had the cat replaced. Car ran better but still not great. Took it to another place, spark plugs replaced, throttle body cleaned and fuel injector cleaner added to gas.
Still the car ran sluggish and was making noise and check engine light was on. Took it to parts store to have code checked on check engine and said error in bank one of oxygen sensor. I replaced that, reset the light and am sure you know, it still runs bad and noisy and check engine light came back on.
I am losing power on hills and big hills the engine rattles. I am at my wits end as I’ve now had three different mechanics look at this with the same original issue.