Poor Fuel Economy. GMC Truck Savana 2000

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2000 🢒 Savana 🢒 Engine 🢒 Engine Controls - 4.3L 🢒 Poor Fuel Economy

Checks

Action

DEFINITION: Fuel economy, as measured by an actual road test, is noticeably lower than expected.

Preliminary Checks

•	Refer to Symptoms .

•	Check the air cleaner filter for dirt or being plugged.

•	Visually and physically check the vacuum hoses for splits, kinks, and proper connections as shown on the Vehicle Emission Control Information label.

•	Check the owner's driving habits for the following items:

-	The A/C ON full time (Defroster mode ON)

-	The tires at the correct air pressure

-	Any excessively heavy loads being carried

-	Any aggressive driving habits

•	Suggest that the owner fill the fuel tank and recheck the fuel economy.

•	Suggest that the driver refer to Important Facts on Fuel Economy in the owner's manual.

Fuel System Checks

•	Check the fuel type, quality, and alcohol content. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

•	Check the fuel pressure. Refer to Fuel System Diagnosis .

Ignition System Checks

•	Check the spark plugs. Remove the spark plugs and check for the following:

-	Any wet plugs

-	Any cracks

Any wear

-	An improper gap

-	Any burned electrodes

-	Heavy deposits

•	Check for an open ignition control (IC) circuit.

•	Check the ignition wires for the following items:

-	Any cracking

-	Any hardness

-	The proper connections

•	Check the knock sensor (KS) system operation.

Cooling System Checks

•	Check the engine coolant level.

•	Check the engine thermostat for always being open or the wrong heat range.

Additional Checks

•	Check the transmission shift pattern. Refer to Automatic Transmission-4L60-E.

•	Check for torque converter clutch (TCC) operation. Refer to Diagnostic Starting Point - Automatic Transmission in Automatic Transmission-4L60-E.

•	Check for proper calibration of the speedometer.

•	Check for dragging brakes.