Loss of Power, Gains, HP

[350VortecSSCT]

While Driving or from dead stop, ill give it quarter throttle and hammer it down and it wont respond for full gas pick up...if anything it just gets louder and moves slowly to climbing speed.

Ill have my foot already on the gas, press it down to 3/4 throttle and it wont gain.

How could I lose power??!?

I changed oil, spark plugs, and fuel filter (usually it was a bad fuel filter) not this time

I already know my Intake Manifold Gasket is leaking...is there a difference between that and a Lower Intake Manifold Gasket Leak or is it the same??

Could I lose power from that?!/

 

[am92]

Is your truck throwing any codes? There are upper and lower intake manfold gaskets. The lower ones are the ones that usually leak but you'll have to replace both when you go to fix it. Most people recommend the fel-pro kit http://www.jegs.com/i/Fel+Pro/375/MS98000T/10002/-1
Yes you could lose power from that and I recommend you fix the problem immediately before you cause any serious engine damage, good luck man