missilex40

Just purchased 94 300zx NA about a month ago. The hydraulic clutch had been replaced right before I purchased. A couple of days after driving started having trouble with the clutch. It has been back to shop 3 times for adjustments, 1st clutch to the floor, 2nd the car wouldn't go into gear, and now after the car is driven about a half hour the car will rev rpm's up in 2nd and 3rd gear when trying to accelerate instead of gaining speed. Once you let up off the accelerator some, it very slowly gains speed. I took to a transmission place and he took for test drive and found no issue with the clutch, but said it seems more like a "driveability issue"...don't know what that means. I do know the previous owner had a lot of work done last year, new trans., slave cylinder, master cylinder, etc. Very frustrated Hope someone can tell me where to start. Thanks!