can a gasket leak cause this??

i have lost power in the last 4 days since i installed a new intake manifold, and i get this deep gargling sound when i press the gas while in gear, when it makes that sound i feel like ive lost power but as soon as the sound stops i get it back but if i keep the car in nutral and step on the gas it sounds just fine...

also, my gas milage has gone from an average of 19mpg down to 13mpg

 

What did you torque the bolts down to?

 

im not really sure... what happened was my buddy installed the kinetix v+ plenum in my car, it has these cork gaskets already attached to the part, well my friend also put my old gaskets on, then my friend who is a tech at nissan noticed that and said that is probably my problem

 

I believe the cork gasket replaces the original one. There would be no reason to have 2 gaskets....

 

your right, but i did not know that until now... so i have both on at the moment and my friend believes that is whats causing all the problems.. im just curious if others agree with him

 

also do you think by now there both damaged?

 

Nah, the bolts aren't torqued down enough to cause any real damage. Just inspect the new gasket for any abnormal indentions or tears. If it looks relatively flat/smooth, re-use it.