Sounds like some tuning issues... see what the current map is and likely will need to return to base with upmap but take it one step at a time before doing that. Do you have any history on the modifications or past owners?
Yeah nobody read that.
Also, there's this cool site called google.com you can do a ton of research on all by yourself. Pretty amazing tech they got these days.
Well it won’t give less than 15 mph. And it doesn’t like being in 4th+ at less than like 80-90.
Have you got the items figured out or still need help? Let us know the progress