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The run on condition is considered normal by chevrolet, It is because the starter is controlled through the computer. I will include the factory bulliten below.
If it is hard to start sometimes when the engine is warm then the PCM needs to be recalibrated by the dealer due to a programming issue with the EGR valve.
Bulletin No.: 03-06-03-001DDate: August 02, 2007INFORMATIONSubject:Starter Cranks After Key Is Released (Normal Condition)Models:2003-2008 Passenger Cars and Trucks (Including Saturn)2003-2008 HUMMER H2, H32005-2008 Saab 9-7XAttention: This bulletin ONLY applies to vehicles with PCM/ECM controlled starters.Supercede:This bulletin is being revised to update the models and model years. Please discard Corporate Bulletin Number 03-06-03-001C (Section 06 - Engine/Propulsion System).Some customers may comment that the engine starter will continue to run after the key is released.For the 2003 through 2008 model years, the Powertrain Control Module (PCM) or Engine Control Module (ECM) controls the starter relay based on input from the key switch. When the ignition switch is held in the start position for 0.4 seconds, the PCM/ECM start timer is activated. Once the start timer is activated, the PCM/ECM will continue to crank the starter until either the engine starts or a no start time limit is reached.Occasionally, the fuel pump module will take one or two seconds to build fuel pressure. Often this will occur after the vehicle sits overnight. During some vehicle starts, the customer may release the ignition switch key before the engine actually starts. When this occurs, the engine will then continue to crank until the engine starts or the no start time limit is reached.This is a normal condition and no repairs should be attempted for this condition.
The hard start is not normal and may require the you pcm be reprogrammed.
The starter run on is the only part they consider normal.
You won't get 300k out of the malibu, but it is not bad. This should run from $100 to $200 depending on the way the dealer bills it.
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