Chevrolet Silverado / GMC Sierra. Manual - part 7
Check for the correct oil level, proper oil viscosity, and correct filter application.
Verify the exact operating conditions under which the concern exists. Note factors such as
engine RPM, ambient temperature, engine temperature, amount of engine warm-up time,
and other specifics.
Compare the engine sounds, if applicable, to a known good engine and make sure you are
not trying to correct a normal condition.
Intermittent
Test the vehicle under the same conditions that the customer reported in order to verify the system
is operating properly.
Symptom List
Refer to a symptom diagnostic procedure from the following list in order to diagnose the
symptom:
Base Engine Misfire without Internal Engine Noises
Base Engine Misfire with Abnormal Internal Lower Engine Noises
Base Engine Misfire with Abnormal Valve Train Noise
Base Engine Misfire with Coolant Consumption
Base Engine Misfire with Excessive Oil Consumption
Engine Noise on Start-Up, but Only Lasting a Few Seconds
Upper Engine Noise, Regardless of Engine Speed
Lower Engine Noise, Regardless of Engine Speed
Engine Noise Under Load
Engine Will Not Crank - Crankshaft Will Not Rotate
Engine Compression Test
Oil Consumption Diagnosis
Oil Pressure Diagnosis and Testing
Oil Leak Diagnosis
Drive Belt Chirping, Squeal, and Whine Diagnosis
Drive Belt Rumbling and Vibration Diagnosis
Drive Belt Falls Off and Excessive Wear Diagnosis
Drive Belt Tensioner Diagnosis
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado
BASE ENGINE MISFIRE WITHOUT INTERNAL ENGINE NOISES
Cause
Correction
High oil pressure
Verify oil pressure. Refer to Oil
Pressure Diagnosis and Testing.
Repair or replace damaged components
as required.
Worn, damaged, or improperly installed
accessory drive belt - severe cracking, bumps
or missing segments
A misfire DTC may be present without an
actual misfire condition.
Inspect the accessory drive system
components.
Repair or replace damaged components
as required. Refer to Drive Belt
Replacement.
Worn, damaged, or improperly installed
accessory drive system components
A misfire DTC may be present without an
actual misfire condition.
Inspect the accessory drive system
components.
Repair or replace damaged components
as required.
Damaged, loose or improperly installed
crankshaft balancer
A misfire DTC may be present without an
actual misfire condition.
Inspect the crankshaft balancer.
Repair or replace damaged components
as required. Refer to Crankshaft
Balancer Replacement.
Worn, damaged, or improperly installed
crankshaft reluctor wheel
A worn or damaged crankshaft reluctor wheel
can result in different symptoms depending on
the severity and location of the wear or
damage.
Systems with electronic
communications, DIS or coil per
cylinder, and severe reluctor ring
damage may exhibit periodic loss of
crankshaft position, stop delivering a
signal, and then re-sync the crankshaft
position.
Systems with electronic communication,
DIS or coil per cylinder, and slight
reluctor ring damage may exhibit no
Inspect the crankshaft position sensor.
Inspect the crankshaft reluctor wheel.
Inspect the crankshaft.
Repair or replace damaged components
as required.
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado
loss of crankshaft position and no
misfire may occur. However, a DTC
P0300 may be set.
Systems with mechanical
communications, high voltage switch,
and severe reluctor ring damage may
cause additional pulses and effect fuel
and spark delivery. A DTC P0300 or
P0336 may be set.
Damaged, loose or improperly installed
engine flywheel
A misfire DTC may be present without an
actual misfire condition.
Inspect the flywheel.
Repair or replace damaged components
as required. Refer to Engine Flywheel
Replacement.
Damaged, improperly installed or restricted
exhaust system, collapsed or dented pipes,
plugged mufflers or malfunctioning catalytic
converters
A DTC may be present without an actual fault
condition.
Inspect the exhaust system components.
Repair or replace damaged components
as required.
Worn, damaged or improperly installed
vacuum hoses
Inspect the vacuum system components.
Repair or replace damaged components
as required.
Damaged or improperly installed MAP
sensor, sealing grommet nicked, torn or
missing
Inspect the MAP sensor.
Repair or replace damaged components
as required.
Damaged or improperly installed throttle
body
Inspect the throttle body.
Repair or replace damaged components
as required.
Damaged or improperly installed intake
manifold
Inspect the intake manifold.
Repair or replace damaged components
as required.
Damaged or improperly installed cylinder
head
Oil consumption may or may not cause the
engine to misfire.
Inspect the spark plugs. Refer to Spark
Plug Inspection .
Verify engine compression. Refer to
Engine Compression Test.
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado
Inspect the cylinder heads.
Inspect the engine block.
Repair or replace damaged components
as required.
Worn, damaged or loose valve rocker arm
Inspect the valve rocker arms.
Repair or replace damaged components
as required.
Worn, damaged or loose valve rotator
Inspect the valve rotators.
Repair or replace damaged components
as required.
Worn, damaged, loose or broken valve spring
Inspect the valve springs.
Repair or replace damaged components
as required.
Worn, damaged or stuck valve, carbon on the
valve stem or valve seat
Inspect the valves.
Inspect the valve guides.
Repair or replace damaged components
as required.
Worn or damaged valve guide
Inspect the valve guides.
Inspect the valves.
Repair or replace damaged components
as required.
Worn, damaged, loose or bent valve push rod
Inspect the valve push rods.
Repair or replace damaged components
as required.
Worn, damaged or dirty valve lifter
Inspect the valve lifters.
Inspect the camshaft.
Repair or replace damaged components
as required.
Worn or damaged camshaft lobe
Inspect the camshaft.
Inspect the valve lifters.
Repair or replace damaged components
as required.
Worn, damaged or loose timing chain and
Inspect the timing chain and sprockets.
2008 Chevrolet Silverado 1500
2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado