I recently just replaced my original transmission and Yank TT2600 stall converter with a PerformaBuilt Level II and 10.5" 3000 Stall Billet Converter. After the install, my truck has been stalling much more than it ever has. I have a Wheatley Tune for my cam (216/222) and ever since I got the cam install/tune done it has stalled some but only if I did not let it warm up and started to drive away on the coldest days of the year. Now it seems that no matter what engine temp is or ambient temp is, it will stumble/search/stall at idle/low rpms. (below 1000) I cleaned the TB very good and still no help. The truck sat for (2) months prior to the install but I have ran a full tank plus fuel system cleaner in it and no change. I have 14.2 Volts at idle at the alternator. I have 50 PSI fuel pressure (key on) and 60 psi at idle. Any help would be appreciated.

 

It sounds to me like you need to have some specific idle tuning done.

 

I agree on more idle tuning.
When i went from a TB converter to a 9" stall it really affected the idle in gear. Kind of weird but I think it has to do with the amount of resistance due to weight but i'm not sure.
Went to the Circle D 278mm and it wasn't as bad any more.

 

That makes sense...less rotating mass with the smaller converter, which may affect a few things I would imagine, including the misfire counter...