Car jitter when accelerating at highway speeds?

I have an '07 Honda Fit. Winter Tires were recently taken off and All Season's rotated on (2 weeks ago).

Was on the highway today and when stepping on the gas to accelerate the check engine light would blink on and off and the car would jitter a little bit like I was going over bumps and the car would not accelerate.

This was/is intermittent. Sometimes I can step on the gas and be fine and sometimes I step on the gas and I get the check engine light blinking and the car does not accelerate.

Any ideas?

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