Originally Posted by
SiriusC1024
First of all, flashing the GTP file was a bad idea. Look at the tune. All the trans settings are erased. Keep in mind that there's a lot more going on than can be seen by HPT. The tables present are there because the devs created definitions for them. Doesn't mean they got everything. No way to tell what all is different between a GTP file and your original. Could be things like firing order, injector timing, etc.
Write-entire your original file to your vehicle.
Take this attached tune and run a compare (Compare>Open Compare File). Manually copy any difference in the Engine section to the original. Save-as. Write-configuration.
This tune should work. It's assuming you're using the factory 1999 F-body fuel pressure regulator. If that's not the case let me know. Fuel tables setup for the Holley's. Relevant 2000 GTP data transferred over.
Let me know how it goes or if you have questions.