I bought a 04 wrx wagon with 147,000 miles with a "suppose to be" boost leak. Well after doing a boost leak and not finding nothing we did a compression test which all came back fine except cylinder #4 it showed 0 psi. Which i find strange because even if i have bad rings or piston it should register something. My question to you guys is; can it be a valve problem? Maybe shims or something?
Please help me before i spends mayor money on an engine.