Mazda 5

Hello just need a little help here, I have a 2010 Mazda 5 with 167k, have not had any problems till now. At 65-75 mph it starts to hesitate but does not stall. Does anyone have an idea what this could be. Just had an oil change approx. 50 miles ago.
2009 Mazda 5 GT
When did you last:
Clean throttle body?
Clean MAF Sensor?
Replace air filter?
Replace spark plugs?
Replace transmission fluid?

These are the first things I'd suspect for what you're describing.
2010 Mazda 5 Sport
Does the hesitation stop being evident after 75mph? It doesn't do it at all in lower speeds but similar RPMs?

I would assume it's not a transmission issue since the transmission should be in top gear at that point and isn't going to shift.

I am almost guessing that it might be a fuel pump not giving enough gas at the top end.

I would suspenct plugs or wires at lower RPMs. Those generally smooth out at higher RPMs.
2014 Mazda5 Sport auto
I'd check the oil level. It's not uncommon for kids to put too much which will cause running issues and even destroy your cat.