Do you have experience repairing NISSAN Altima’s?

I drive a Nissan 3.5 , it’s been hesitating when I push down on the gas pedal whether driving or in park. Won’t go over 70. At 70 it REALLY hesitates. I haven’t drove it since it started doin this but had to tonight - the exhaust just smells like straight up gasoline. I have 3 codes , p0650 twice, and p0420, I know... show more I drive a Nissan 3.5 , it’s been hesitating when I push down on the gas pedal whether driving or in park. Won’t go over 70. At 70 it REALLY hesitates. I haven’t drove it since it started doin this but had to tonight - the exhaust just smells like straight up gasoline. I have 3 codes , p0650 twice, and p0420, I know 420 is a generic code. I checked removed and cleaned the mass air flow sensor and throttle body today , and air filter. Still does it. Haven’t done anything else. This moron at autozone recommended “cataclean” when I went to buy o2 sensors today.
Does anyone out there have any suggestions? I would like to get opinions before I take it to my mechanic. Since they are so expensive. I can do a tune up myself, or even replace and oxygen sensor. I want to get your opinion with this.
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