I have a similar stalling problem... actually, I talked to several folks that have 3800 engines with the same issue. It seems to be very heat related. When the ambient temp gets above 95 degrees, and you're in stop/go traffic, you can almost bet that when you accelerate out, it will hesitate... uneven acceleration. Worst case, just starve for gas. Very similar sensation to the "right turn out-of-gas" problem described elsewhere in this forum. Let it cool down a little, and it will go again, just like nothing ever happened. The dealer "can't reproduce the issue"... read: they don't want to drive it enough to make it act up.
Save your bucks on the fuel pump. Several folks have tried that... no joy.
Fuel filter? no, that'* new
Plugs and wires? no, they are new
MAF screen and throttle body? I doubt it... they look clean
No codes are thrown...
So... I'd like to find the cause of the problem when it happens. Any advise? Hang a fuel pressure guage after the fuel pressure regulator to see there'* a pressure drop? Is there any input or output to the ignition module that could be monitored while driving? How about vacuum? Somewhere I read that the vacuum will fall during acceleration if the CAT convertor is trying to plug up.