Fueling & Injection - could this be injectors

I currently did a h/c swap and tuned showed I was running lean around 4500. So I bought some 42lb racetronix injectors which fixed the fuel issue but now the car will not idle at 900 like it did with the smaller injectors. When I crank it immediately tries to idle around 450 500 and sounds like it's going to go dead and several times it has went dead. It has ported 243s ls6 intake and ported TB and raptr cam. Any help is appreciated.

yes, you need to re-tune for the larger injectors.

I had it re tuned. That's what I don't get. Guy tuning it can't get it to idle like before and I have no idea what else it could be.