DRIVEABILITY AND EMISSIONS 6E1-95
Poor Fuel Economy Symptom
Step Action Value(s) Yes No
DEFINITION: Fuel economy, as measured by an actual road test, is noticeably lower than expected. Also, economy
is noticeably lower than it was on this vehicle at one time, as previously shown by an actual road test.
1
Was the On-Board Diagnostic (OBD) System Check
performed? -
Go to Step 2
Go to OBD
System
Check
2
1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
-
Verify Repair Go to Step 3
3
Was a visual/physical check performed?
-
Go to Step 4
Go to
Visual/Physic
al Check
4
Check owner's driving habits.
• Is the A/C On full time (defroster mode ON)?
• Are tires at the correct pressure?
• Are excessively heavy loads being carried?
• Is acceleration too much, too often?
-
Go to Step 5 Go to Step 6
5
Review the items in Step 4 with the customer and advise
as necessary.
Is the action complete?
-
System OK
-
6
1. Visually/Physically check: Vacuum hoses for splits,
kinks, and improper connections and routing as shown
on the "Emission Control System schematics".
Was a problem found?
-
Verify repair Go to Step 7
7
Remove and check the air filter element for dirt or for
restrictions.
Was a problem found?
-
Verify repair Go to Step 8
8
1. Remove the spark plugs and check for gas or oil
fouling cracks, wear, improper gap, burned electrodes
of heavy deposits.
2. Is spark plugs are fouled, the cause of fouling must be
determined before replacing the spark plugs.
Was a problem found?
-
Verify repair Go to Step 9
9
Check for low engine coolant level.
Was a problem found?
-
Verify repair Go to Step 10
10
Check for an incorrect or faulty engine thermostat.
Refer to Engine Cooling.
Was a problem found?
-
Verify repair Go to Step 11
11
Check for low engine compression. Refer to Engine
Mechanical.
Was a problem found?
-
Verify repair Go to Step 12
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