I have a 2010 cobalt ss with 41xxx miles stock tune
Mods:
Injen intake
Hahn downpipe
Injen chargepiping
Turbo xs intercooler
Forge bpv

During a pull pushed 15 maybe 16 psi then check engine flashed

Symptoms
Very rough idle
Random cylinder misfire
Cylinder 4 misfire
Turbo Flutter

Checked coils spark plugs and compression
Found no compression in cylinder 4 but will re check

Any help is appreciated i suspect of a blown piston but i would like a second opinion or other things i should check for the dealer said it could also be a valve or head gasket it just seems odd that 41k miles and stock tune would blow my piston

Thanks

 

Bump

 

Re bump