Base Engine Misfire with Coolant Consumption

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Cause	Correction
Faulty cylinder head gaskets and/or cracking or other damage to the cylinder heads and engine block cooling system passages. Coolant consumption may or may not cause the engine to overheat.	Inspect for spark plugs saturated by coolant. Refer to Spark Plug Inspection in Engine Controls - 8.1L. Perform a pressure test to the cooling system. Refer to Loss of Coolant in Engine Cooling. Perform a cylinder leak down test. Refer to Cylinder Leakage Test . Inspect the cylinder heads and engine block for damage to the coolant passages and/or a faulty head gasket. Refer to Coolant in Combustion Chamber . Repair or replace as required.

Cause

Correction

Faulty cylinder head gaskets and/or cracking or other damage to the cylinder heads and engine block cooling system passages.
Coolant consumption may or may not cause the engine to overheat.

Inspect for spark plugs saturated by coolant. Refer to Spark Plug Inspection in Engine Controls - 8.1L.
Perform a pressure test to the cooling system. Refer to Loss of Coolant in Engine Cooling.
Perform a cylinder leak down test. Refer to Cylinder Leakage Test .
Inspect the cylinder heads and engine block for damage to the coolant passages and/or a faulty head gasket. Refer to Coolant in Combustion Chamber .
Repair or replace as required.