The turbocharged four cylinder was underpowered and wasn't considered appropriate for a vehicle of this type, while neither Chrysler or Mitsubishi had a V6 engine until 1986 when both the Chrysler LA 239 V6 engine and the Mitsubishi V6 appeared.
The lack of power in the four-cylinder turbocharged engine led to its inadequacy for the vehicle type, as neither Chrysler nor Mitsubishi had a V6 engine available until 1986 when they introduced their respective V6 engines.