Mustang GT help please
I have a mustang 50 2017 model with 8000 km on clock.
i have noticed recently that when I come off the gas that it feels like there is almost no engine braking from the v8 and as if there is no compression, and it seems as if the rev counter takes a few moments longer to come down?
I have owned it from new and about 2000 km ago I removed the stock rear muffler boxes and replaced them with aftermarket units to improve the sound a bit, gas mileage improved slightly and performance on aceleration is normal?

any thoughts on this I will appreciate your comments