This is my first ever post, ive been using the forum for a couple years now just never made an account. I cant find any info that could help. Anyways, the car has a new turbo, walnut blasted, new spark plugs & upstream O2 sensor. My tune would see 18 psi WOT but now i only see about 12 psi with a drop to 6 psi at times. Car runs so smooth with no CEL. Is it possible i didnt tighten the exhaust manifold to the turbo correctly? Idk what to think anymore haha