GM Piston Slap

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An abundance of documentation by automotive industry experts is readily available that states "piston slap" engines waste fuel and have significantly higher vehicle emissions due to incomplete combustion, combustion of excessive amounts of lubricating oil and combustion chamber blow-by. The higher levels of fuel consumption and vehicle emissions increase exponentially as the miles accrue, due to the accelerated wear of internal engine components that are the result of critical clearances being excessive. Upon researching the US Environmental Protection Agency’s fleet certification process for emissions, it is obvious these factors were not taken into account. GM’s own documentation in the form of several technical service bulletins (TSBs) confirms the extent of the "piston slap" engine defect. GM TSB #’s 01-06-01-022, 01-06-01-028 and 01-06-01-005 discuss the problem on 1999-2002 3.1, 3.4, 4.8, 5.3, and 6.0 liter engines. 5.7 (LS1) and 8.1 liter powerplants are also affected. These bulletins state the noise "Cold Start Knock" is caused by an interaction between the piston and the cylinder wall. They also explain that this condition should be considered "NORMAL". GM TSB# 01-06-01-011 was released in spring ’01 stating the consumption of a tremendous amount of oil (3.75 quarts of oil between oil changes) on new engines (0-36k miles) is to be considered "NORMAL" as well. It appears to even the most casual observer that this TSB on oil consumption was put in place in an attempt by GM to prevent having to repair these defective "piston slap " engines.

More info at:
http://www.pistonslap.com/tsb.htm