07 Silverado 5.3 4×4. Shifting points change manually without a tuner.

[terry beavers]

Looking for a little advise if anyone can help . I just replaced my ignition and key chamber on truck Before I did anything the truck would accelerate fast and shifted like I felt it should. When I would pass someone and lay the peddle down the truck would kick in passing gear fast and then down shift around 4000 rpm which was great. 

 Now it's kinda sluggish from take off and when I put the pedal down. It kicks into passing gear good but it wont down shift into normal drive mode until 5,500 Rpm or when I let off the pedal for a second.

  Any advice and help would be appreciated