2001 GTP 165000 on the clock.

After disconnecting the battery to do some work the car is now stumbling during light acceleration usually between 1500 and 2000 rpms. When it does this the boost gauge on the DIC spikes. If it starts stumbling I can lift of the gas and it goes away. Also, if I go WOT it will initially hesitate, no to low power with the boost indicator spiking 1 to 2 bars and then finally catch. I am at a loss. Don't have a scanner so I don't have any codes that I know of.