Downshift Engine Hesitation

[Shrek427R]

Hi all,
It's been awhile since I've posted a thread here. Low miles and car runs great with one exception. I notice a slight engine hesitation when downshifting from 5th gear to 4th, 4th gear to 3rd while on my local freeways. It lasts for about a half second and seems like the engine needs to take a short breath before engaging power. After this hesitation, the engine engages and power comes on for my acceleration.
I'm the original owner of a 2007 427R with the stock engine and supercharger with only a ECM reflash that was done by Roush several years ago. I have about 22,000 miles on the ODO and changed the stock plugs to a set of one piece Brisks the same time as the ECM reflash.
I don't have an oil separator but this hesitation issue is making me think that it's now a necessary upgrade.
Suggestions?

 

[Dino Dino Bambino]

1. Remove the throttle body and clean it inside out.

2. An air oil separator is always a good idea especially on a forced induction engine since, by nature, it has more piston blowby than a N/A engine.

 

[rawdawg]

Maybe your spark plug gap is too big. Do you have an automatic or manual transmission?