Try this, and it will set a check engine light if your equipped. Pop up the passenger carpet and unplug the O2 sensor, if the hesitation goes away, check the base lambda adjustment (after plugging the O2 back in) if it is in line (35-55%) check for vauum leaks including the vacuum switch on the head for the EZL. Check the throttle plate for sticking and clean it up a bit while your at it. I had one of these doing something similar that had a rusted out freeze plug at the rear of the intake, due to roller noise, you never heard the leak, it had been covered up to a point by way of a overly rich CO adjustment.
Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.