Diagnostic Aids
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
A restricted fuel supply line may cause DTCs P0087 and P1093 to set at the same time. Refer to Fuel System Diagnosis (Pickup) or Fuel System Diagnosis (Cab Chassis) .