Do our 5.5 have the VIAS like the 5th generation maxes? If so could a busted one make our cars have hesitation after 4k rpm? The reason asking, Friday i am getting a full ecm reprogram because i added the am-600 mafs. My car drives fine till about 4500 then goes limp and pulls limp all the way till redline. I know some of you said a ecm reprogram will fix that, but if our VIAS is busted, if we have a VIAS then would that cause the car to hesitate to redline like that?

Also no SES light.... nothing, just poor gas milage and hesitation after 4000 k.
Gas milage went down from 25-17mpg.

I also notice the throttle body is terribly filthy too, car has 90k miles on it. And the funny thing is one morning to work it was strong as a bull and the drive home in the afternoon it was tame as a lamb.

Guys what should i do before friday? Should i get some throttlebody cleaner,and try that? Need your help, thanks.