2007 S40 Sputtering/Hestitation...any advice?

[btmille]

Hey everyone,

I have a 2007 Volvo S40 (no Turbo). It has 55,000 miles on it. To my knowledge (i've owned since 20k), it has never had a tune-up or anything major done.

I am having a problem with some sputtering/hesitating/missing when driving on the highway from about 40mph - 70mph. It doesn't do this when I "floor it". It also seems to idle fine and when going at slow rpm. There is NO check engine light on. Everything seems to be ok and it is minimally noticeable. Also, I put 2 tanks of premium gas through it already and it didn't seem to help at all. I've been driving like this for about 3 weeks now.

Any help would be greatly appreciated.
Thanks!