Battary was water check and charged friday afternoon. Used a bit over the weekend, and a bit this morning. Still 4 out of 5 lights on dash left.
(BTW, reading during acceleration was done with a 10,000v clamp meter and tails, so perfecly safe)

We have adjusted the potentiometer to various settings, but to no avail. We seem to have creep speed, and max speed, but nothing in between :(

The potentiometer is brand new, and reading ok on a meter at various settings, the wires going into the PCB also read the same as at pedal. Cant say for certain the condition of the main motor cables (am i right in assuming there are more than 1 pr of cables to the main motor?)

Im thinking either worn motor (whats the symptoms) or logic out of adjustment.

How long had the battery been off the charger and being used? also, we need to be able to read 1/10 volts to be able to do the math correctly.
If this is a freshly charged battery, you have battery problems. if this is a battery that has ran for 4 hours, then it is not -all- that bad, but not "good", either.
Reading voltage during acceleration is worthless, and *dangerous*, it can change based on the load of the drive motor (level floor, amount of pedal, speed already reached when reading) as well as the fact you may be reading currents that are not from the battery, but generated in the controller (some controllers have 2x battery voltage in some areas, because of the electronics).
The acceleration is controlled initially by a variable resistor (potentiometer) attached to the accelerator pedal, (accel pot) but is also adjustable for fine tuning within the controller's logics. your problem may well be in the traction controller, the accel pot, the linkage, or the wiring.
There are a few types of 'speeds' in an electric truck, (creep, current limit, controlled acceleration, 1a time, 1a drop-out) and they work together, so an adjustment of 1 may affect other settings, and these things often require a special handset to adjust, and special training to safely adjust (and your forklift is not safe to operate the way it is now)

Ok, volts at rest = 74. Volts at stalled tilt = 66. Just about 10%.
Volts at acceleration = 73. Seems the battery is OK. If i adjust the pedo in the pedal to max, the truck takes off like a rocket, with wheelspin and whiplash. Ive tried many adjustments on the pedo switch, and nothing :(

What controls the acceleration? is it a mechanical switch, or is it all controlled by the PCB?

1st, what is the battery condition under load? (read battery volts at rest then when tilt is stalled all the way, in or out, compare) if more than a 10% drop in voltage, then charge or fix the battery first.
Next you have some adjustments available in the logics, (current limit, controlled acceleration, etc) but this is not for someone that has not been trained to understand what the differences are and how they effect other settings in the logics, and depending on the system your truck has in it, it may require a "handset" or other high dollar gages/meters to be able to correctly measure and set the control logics.