I had the same thing on mine... Couldn't shift into 3rd at higher RPM's just horrible grinding. If I'd get into higher rpm's, push in the clutch let the rpm's drop I could get it into 3rd. In the end, bad 3rd gear syncro, bad 3rd gear, replace 4th gear sychro, plus misc. parts and a whole bunch of labor (10+ hours). Luckily I had JUST bought the car so it was under the 30 day/1,000 mile warranty.
Paul
