I'm just curious. With a Nistune installed and tuned does it retain the ability to switch mapping or alter via codes For example, code 34 (DET sensor) is thrown will this alter the map for increased fuel?) Or alternatively, if a coolant temp sensor code was triggered (code 13) would this throw it into a different fuel map or ignition map? Or does the Nistune and tune on it disable this feature apart from registering codes?
Yes and No. Depends how it's tuned. All Nistune really does is provide access to the maps/configuration with rewrite saving of your changes. So it's up to you if you leave these maps active or not.
Saftey/knock maps are still active, but most tuners copy their tuned maps into the saftey maps, so ecu will still switch but they will be looking at the same values anyway.
Based on this info. Would I be able to use a switch to use both sides and remove the safe mode. Use the switch to go into 98 and e85?
You'd need two separate tunes...... the two fuels would need changes to injector K values, not just different fuel/timing maps.