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?

So you have a engine miss and for some reason your talking about the tires. What is that about? Go get the codes read and Google the numbers.

Mileage would help but JJ is bang on.

There are no codes. The check engine light blinks on and blinks off. No codes or anything. I only mention tires because I know nothing about cars and this was a recent change. Maybe it's relevant, maybe it's not. I'm not an expert that's why I'm asking here. If it's not relevant someone will say so, hopefully in an understanding way and not in a condescending way.

85,000 km on the car