No.
http://www.instant-radio-code.co.uk/chrysler-jeep-code-search.php
Diagnostic code 43 in the 1997 Jeep Grand Cherokee refers to an issue with the distributor. This often causes the Jeep to stall at operating temperature.
no
No.
Yes they should interchange without a problem.
http://www.jedi.com/obiwan/jeep/dtc.html
Error code 66 on a 1997 Jeep Cherokee means TCM to PCM failure. This code means that the transmission control model is not communicating with the powertrain control model.
A 1991 Jeep Cherokee computer is what fits a 1991 Jeep Cherokee.
O2 sensor or wiring
Throttle position sensor out of range.
Cylinder #1 misfire.
catalytic converter circuit