Long answer:
Barring anything being mechanically wrong with the car, there could be a number of reasons why your throttle response through first gear would be bad. The first question being, do you have any codes? Also, is it an auto or five speed? Timing still at the factory 10° BTDC setting? Normal maintenance parts are all in good condition?
I had the same problem after my tranny swap. I thought that first gear in my new tranny sucked. Then I found out that a little tune-up is all in needed. specially the maf. If you have a KandN or any open air filter, chances are your maf is dirty.oh, and I had codes popping up but no CEL. so, clean MAF sensor.