1993 Grand AM Sedan SE engine code

I'm trying to track down the engine and transmission code for my '93 SE, 3.3. I'm having tranny problems, won't shift out of 1st unless you put it up to redline. I've noticed you can get a 1993 Buick Century with the 3.3 and a 4-speed auto. I'd like to put this tranny in my car if I have to do any major transmission work. Does anyone out there know if this is possible. Also, any ideas on that tranny problem?

I might as well ask about some engine problems too. The engine is missing when it idles, then when you step on it, it seems to catch on all 6. I'm wondering if one of the injectors is a little weak. I just did plugs and wires. Can I disconnect the injectors one at a time and see if I can isolate which cylinder it is. I'm going to clean the MAF sensor, this seems to be a common problem with the 3.3.

Thanks.

chances are they are the same tranny

I should clarify, the tranny in the car right now is a 3 speed auto.

I replaced my 1993 3.3V6 3-speed auto... with a 1993 3.3V6 Buick Century 3-speed auto. My mechanic tried a 4-speed Grand Am trans, but it wouldn't fit.. so, i would think a 4-speed Century wouldn't either.. but i don't know..