here is the warranty policy on the Tier 2 & 3 Clark Woodward systems.

all warranty work MUST be performed by your local Clark dealer to obtain factory warranty.

EPA COMPLIANT FUEL SYSTEM WARRANTY
For 36 months after the product has been installed, CLARK warranty will cover the
replacement or repair of fuel system components excluding the fuel tank, spark plugs
and wires, and the labor to install them provided the truck use has not exceeded 2500
hours.
The components covered are:
 Fuel Lock off
 Vaporizor / Regulator / EPR
 Carburetor / Mixer
 Fuel Trim Valve
 Ignition Coil
 Distributor Cap
 Rotor
 Fuel System Thermostat
 O2 Sensor
 Engine Control Module / ECU / SECM*
 Electronic Throttle Control*
 Catalytic Muffler*
 Map Sensor
 Fuel Rail
 Fuel Injector / Fuel Nozzle
*NOTE:
Additionally, for up to 60 months from the installation date, CLARK warranty will cover
the replacement or repair of the Catalytic muffler, Engine Control Module / SECM or
Electronic Throttle Control provided the truck use has not exceeded 3500 hours.
Component serial numbers are required on warranty claims for work performed on
vaporizer/regulator, mixer/carburetor or the Engine Control Module / SECM. The
Engine Fault Code which was determined to be the cause of the component
replacement should also be included in the work description on the claim.