Hesitation upon acceleration?

What is your question?

2008 Nissan Versa 1.8L 6speed tranny. hesitation when throttle, held between 1800 and 2500 RPM. The check engine light has never come on. The hesitation is not noticeable in 4th. thru 6th. gear, as RPM is usually higher. Scan check used but no history of faults in system! The hesitation has become more noticeable over past month, to 6 weeks. The fuel economy has decreased slightly to 26 MPG for the last 2 tank fulls, from 28.5 MPG. Mixed city/highway driving. Highway speeds do not seem to be effected, nor do lower gears with higher RPMs?

What makes this problem better or worse?

Higher RPMs, it is better. steady RPMs or in the 1800 to 2500 range it is worse!

How long has your 2008 Nissan Versa had this problem?

6 weeks