94 gt alternator problems?

[Krono353]

Okay today I just got my alternator replaced and the car was fine for awhile. But when I would get into higher gears like 3rd and 4th that car would buck and the power locks would like lock then unlock and the gauges would mess up. Like the rpms would go to 0 then go back up, same with the mph. But the very last time it happened the gauges stayed low and the car wouldn't go even though it was moving, I'd shift into lower gears and I think the engine was going but the car wouldn't go any faster. So I pulled over and tried starting it but it wouldn't start. Cranked just fine the way it normally would. The lights stayed on until i turned them off and the light on the inside did the same. About 5 minutes later I tried and it fired right up. I can't say I was nice to the car after that, I kind of went a little driver crazy on it but I think it will be fine. But not the problem I experienced. Any ideas what it could be? Oh yes the alternator before worked and never did what the new one just did. I had a gauge problem with it and the mechanic I took it to replaced the alternator.