Code po446 15 chevy suburban lt
 

Hello everyone,

. I have a 2015 suburban it 136k miles. Have a check engine with code po446, which I've gathered relates to EVAP system. But yesterday on the highway I couldn't drive my car past 65-70mph. At 3500rpm would go 70mph. Decided to get off the highway and then it wouldn't go past 35mph(3500rpm). I was under the impression that it was a transmission issue. But later in the day, I had a mechanic test drive it and ofcourse the transmission shifted perfectly fine. Went up to 100mph crisp, with no problem. If anyone is familiar with this problem, I would really appreciate some info about it. THANK YOU!

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