Chevrolet 2011 Express 1500 Cargo Owner's Manual page 304

Among those acts presumed to
constitute tampering are the acts
listed below.
Removal of the noise shields or
any underhood insulation.
Removal or rendering engine
speed governor, if the vehicle
has one, inoperative so as to
allow engine speed to exceed
manufacturer specifications.
Removal of fan clutch, if the
vehicle has one, or rendering
clutch inoperative.
Removal of the fan shroud, if
the vehicle has one.
Removal of the air cleaner
silencer.
Modification of the air cleaner.
Removal of the muffler and/or
resonator.
Removal of the exhaust pipes
and exhaust pipe clamps.
Removal of the muffler.
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could
be injured.
1. Before starting this check, be
sure there is enough room
around the vehicle.
2. Firmly apply both the parking
brake and the regular brake.
See
.
Do not use the accelerator
pedal, and be ready to turn off
the engine immediately if it
starts.
3. Try to start the engine in each
gear. The vehicle should start
only in P (Park) or N (Neutral).
If the vehicle starts in any other
position, contact your dealer
for service.