my 05 wont shift above 6k, its like somthings blocking it, but when it drops down around 4500 it slips right in. it did this with the stock shiffter so i got an mgw and it still does it.
Too much flex in the drivetrain. It's pretty common, though a new shifter sometimes helps. Since that didn't help, here's what you need. http://www.cheperformance.com/cartgenie/prodInfo.asp?pid=208&cid=15 http://www.stangsuspension.com/store/comersus_viewitem.asp?idproduct=721
that could be it my car is far from stock(360 rwhp). i thought it did this brand new but that could have been the shifter binding up.
Mine are modded very similarly to one another, but the '05 is the one I had the issue with getting into 3rd gear with. I don't know, it may be more prevalent in '05s. Either way, even stock or with basic bolt-ons, I've noticed this issue with the '05. The shifter resolved it for me, for now. But I fully plan on replacing the k members on both with built-in motor mounts and torque limiters.