When I first bought my 06 6mt I was having a problem with stutter/bucking when accelerating or just cruising at a constant speed it would every so often when in was nice out but when it was raining or snowing it would happen quite frequently so my first step was a fuel cleaner which did nothing to help. So I did some searching and somehow came across a thread the mentioned something about a MAF, the post didnt have the exact symptoms but was similar. I figured I would give it a try though, went to auto zone and got MAF sensor and a new filter because I was going to have to take it out anyway. Clean the MAF changed the filter and what do you know fixed the problem! Don't know if it was one or both that fixed the problem but I thought I would post this so hopefully it could help someone else out.