Shifting issues

[karnage42]

The other day my magnum rt started shifting strange, between 4-5 it felt like the tcc was kicking in and out. Checked fluid, its fine, clean not burnt. I reloaded the tune and put in shift firmness and tires size again. Is there a chance it lost the tune somehow?? It shifts great now and pulls hard. I also installed a flowmaster catback. Now it pops a little in the exhaust. Can a change in fuel make it pop less kinda like a bike tune for 4 into 1 exhaust.

Thanks

[mikel]

No, the tune cannot change on its own.

[karnage42]

I reset tcm learning and my shifting is good. Doesn't explain why my tire size was lost and firmness wasn't on.