I have an 06 model with a Vortech, with just about every aftermarket part you can put on it. I recently took my car to the shop because my AF's were going lean into the 16-17 range and it has also developed a slight miss. The current tune put down 438 rwhp with 350ish torque, EMS is the HKS F-Con with Knock amp. I know the tune hasn't changes so were looking into a parts failure.

Which leads to my question we first did a compression test and leak down test. Five cylinders were 150 psi and one was 145. Factory specs say the motor should produce between 142 to 182 PSI, I'm trying to understand why my compression is so low. The leak down test showed 0% leak down in all cylinders so wheres the extra 30 plus psi? I'm not terribly concerned but I'm just trying to understand why this is. We have sent the injectors out for cleaning and a flow test to see if I have a bad injector, plus we are replacing the spark plugs hoping to get rid of the miss. At any rate the AF problem may be a combination of things but were starting with the basics and going from there. We'll if someone smarter then me has some idea's i'd like to hear em! Thanks