Why does my 2003 Chevy Silverado 2 door pickup LQ4 Vin U engine Why does my 2003 Chevy Silverado LQ4 engine have no compression in one cylinder
There are several reasons, all of which are reasonably large problems:
- The spark plug is missing.
- One or more of the valves is broken or stuck.
- The piston is messed up or the piston rings are damaged.
- The cylinder head is broken or the head gasket is damaged.
- The engine block is broken.
I'd start by checking what I could from the outside. If you have a borescope remove the spark plug and have a look inside.
Pull the cylinder head and see what's going on inside.