Driving issue
 

I have an '03 TrailBlazer ext 5.3l and I just had to take it to the transmission shop. They said the torque converter was fried. They replaced it and now it shifts fine but I have a severe misfire and horrible fuel consumption. I thought it was the maf but I replaced it with no change. It will run fine for a few mins or a mile or so and then tries to die. Acts like it's flooding the fuel. Any ideas? It was running fine just not shifting. Now it shifts but wont run. The shop of course said they didn't nothing but the trans and this is a separate issue and not their problem. Any help is appreciated.