over the winter i picked up zzp stg 3 kit. after installing for the first few months my boost gauge was hitting 20 psi. for some reason now it only manages at the most 17 psi. anyone have any idea of what could be wrong?

 

clogged cat

 

a clogged cat would result in higher psi.

the colder air would normally produce higher psi because the air is denser in the winter. hot air is thinner, so the psi would be lower.

Are you throwing any codes? does the car feel fine still? is your loss of power actually a loss of power, or just the boost needle not pushing 20 anymore? psi does not always mean power. psi is a measurement of restriction at the intake manifold. also if u have installed anything exhaust wise would be another reason you "lost" psi. all you did was make ur system flow better.

 

i had a full exhaust already on before i installed the kit. no codes, and yes the car still feels fine. maybe it is the weather issue.