idle question with TH350...yes i have searched

[acrider2]

I have a LS1 from a '00 Camaro in my rock crawler with a TH350. It idles fine when it is in neutral but when i put it in gear it will drop to 300-400 rpm before it catches itself. sometime is won't catch and just dies. Once it stabilizes it will idle fine. I have a M6 tune on it right now. I have searched but haven't found much info on idle tuning with a TH350. I am thinking most people with a tranny swap have large stalls and don't notice this problem. Mine has a stock converter. I'm not expeting someone to tell me the magic thing I need to do to fix it but if someone could point me in the right direction it wound be appreciated. Gas tuning is so much more complicated than diesel

[ChipsByAl]

The tune you have in your PCM is for a stick. It does not recognize when you change from neutral to "in gear" and cannot compensate. You could rig a park/neutral switch in your shifter or mechanism and give the signal to the PCM. You would also need to go with an auto program and just delete most of the tranny codes.
Al