vibration

[jmwilso2]

Hi everyone I just got my gryphon a week ago and have been on a road trip half way accross canada since then I've been trying out the different canned performance tunes and am finding that the 87 towing gives me the best over all driveablility and fuel economy but both it and the 93 performance have a small but very noticable vibration when in 4th gear and under load. For example when accelerating gently, it occurs immediately after shifting to 4th. Or if going up hill at lower speed like 35-45 mph. Once I get up to highway speed the vibration goes away. It feels like it is coming from the tranny but I cant be certain. Has anyone else experienced this and if so did it go away when you got your custom tunes?

Thanks

Joe