4.8 to 5.3 Swap. Engine in but I need troubleshooting help.

[mopower440]

you ever figure out the problem?

[yellowbu]

mine was doing something similar. I replaced the iac, went thru the idle learn procedure. Replaced the maf sensor. still had the prob. I had a ver slight vacuum leak at the intake gaskets. Replaced the intake gaskets and it idles smooth as new.