WARNING:  Do not remove or alter the original equipment floor covering or insulation between it and the metal floor of the vehicle. The floor covering and insulation protect occupants of the vehicle from the engine and exhaust system heat and noise. On vehicles with no original equipment floor covering insulation, do not carry passengers in a manner that permits prolonged skin contact with the metal floor. Failure to follow these instructions may result in fire or personal injury.

U.S. federal laws and certain state laws prohibit removing or rendering inoperative emission control system components. Similar federal or provincial laws may apply in Canada. We do not approve of any vehicle modification without first determining applicable laws.
Missing Image  Tampering with emissions control systems including related sensors or the Diesel Exhaust Fluid system can result in reduced engine power and the illumination of the service engine soon light.
Tampering With a Noise Control System
Federal laws prohibit the following acts:
  • Removal or rendering inoperative by any person other than for purposes of maintenance.
  • Repair or replacement of any device or element of the design incorporated into a new vehicle for the purpose of noise control prior to its sale or delivery to the ultimate purchaser or while it is in use.
  • The use of the vehicle after any person removes or renders inoperative any device or element of the design.
The U.S. Environmental Protection Agency may presume to constitute tampering as follows:
  • Removal of hood blanket, fender apron absorbers, fender apron barriers, underbody noise shields or acoustically absorptive material.
  • Tampering or rendering inoperative the engine speed governor, to allow engine speed to exceed manufacturer specifications.
If the engine does not start, runs rough, experiences a decrease in engine performance, experiences excess fuel consumption or produces excessive exhaust smoke, check for the following:
  • A plugged or disconnected air inlet system hose.
  • A plugged engine air filter element.
  • Water in the fuel filter and water separator.
  • A clogged fuel filter.
  • Contaminated fuel.
  • Air in the fuel system, due to loose connections.
  • An open or pinched sensor hose.
  • Incorrect engine oil level.
  • Incorrect fuel for climatic conditions.
  • Incorrect engine oil viscosity for climactic conditions.
Note:   Some vehicles have a lifetime fuel filter that is integrated with the fuel tank. Regular maintenance or replacement is not needed.
Note:   If these checks do not help you correct the concern, have your vehicle checked as soon as possible.
Noise Emissions Warranty, Prohibited Tampering Acts and Maintenance
On January 1, 1978, Federal regulation became effective governing the noise emission on trucks over 10000 lb (4,536 kg) Gross Vehicle Weight Rating (GVWR). The preceding statements concerning prohibited tampering acts and maintenance, and the noise warranty found in the Warranty Guide, are applicable to complete chassis cabs over 10000 lb (4,536 kg) GVWR.