Hesitation, Sag, Stumble
Step 
 | Action 
 | Value(s) 
 | Yes 
 | No 
 | 
Definition: Momentary lack of response as the accelerator is pushed
down. Can occur at all vehicle speeds. Usually most severe when first trying
to make the vehicle move, as from a stop sign. May cause engine to stall if
severe enough. 
 | 
1 
 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? 
 | -- 
 | 
Go to Step 2
 
 | Go to 
Powertrain On Board Diagnostic (OBD) System Check  
 | 
2 
 | 
- Perform a bulletin search.
 
- 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? 
 | -- 
 | 
Go to Step 16
 
 | 
Go to Step 3
 
 | 
3 
 | Perform the careful visual/physical
checks as described at the start of  Symptoms
 section. 
Is the action complete? 
 | -- 
 | 
Go to Step 4
 
 | -- 
 | 
4 
 | 
- Check the TP sensor for binding or sticking. Voltage should increase
at a steady rate as the throttle is moved toward Wide Open Throttle.
 
- Repair if found faulty.
 
 
Was a problem found? 
 | -- 
 | 
Go to Step 16
 
 | 
Go to Step 5
 
 | 
5 
 | 
- Check the MAP sensor for proper operation. Refer 
Manifold Absolute Pressure Sensor Output Diagnosis 
.
 
- Repair if found faulty
 
 
Was a problem found? 
 | -- 
 | 
Go to Step 16
 
 | 
Go to Step 6
 
 | 
6 
 | 
- Check for fouled spark plugs.
 
- Replace the spark plugs if found faulty.
 
 
Was a problem found? 
 | -- 
 | 
Go to Step 16
 
 | 
Go to Step 7
 
 | 
7 
 | 
- Check the Ignition Control Module for proper grounds.
 
- Repair if grounds are found faulty.
 
 
Was problem found? 
 | -- 
 | 
Go to Step 16
 
 | 
Go to Step 8
 
 | 
8 
 | 
- Check for poor fuel pressure. Refer to 
Fuel System Diagnosis 
.
 
- If a problem is found, repair as necessary.
 
 
Was a problem found? 
 | -- 
 | 
Go to Step 16
 
 | 
Go to Step 9
 
 | 
9 
 | 
- Check for contaminated fuel.
 
- If a problem is found, repair as necessary.
 
 
Was a problem found? 
 | -- 
 | 
Go to Step 16
 
 | 
Go to Step 10
 
 | 
10 
 | 
- Perform the 
Fuel Injector Solenoid Coil Test 
 and 
Fuel Injector Balance Test 
.
 
- If a problem is found, repair as necessary.
 
 
Was a problem found? 
 | -- 
 | 
Go to Step 16
 
 | 
Go to Step 11
 
 | 
11 
 | 
- Check for proper system performance. Use Table 
Evaporative Emission Control System Diagnosis 
.
 
- If a problem is found, repair as necessary.
 
 
Was a problem found? 
 | -- 
 | 
Go to Step 16
 
 | 
Go to Step 12
 
 | 
12 
 | 
- Check for proper function of the thermostat. Also check for proper
heat range.
 
- If a problem is found, repair as necessary.
 
 
Was a problem found? 
 | -- 
 | 
Go to Step 16
 
 | 
Go to Step 13
 
 | 
13 
 | 
- Check the generator for proper output voltage. The generator output
voltage should be between the specified values.
 
- If a problem is found, repair as necessary.
 
 
Was a problem found? 
 | 11V-16V 
 | 
Go to Step 16
 
 | 
Go to Step 14
 
 | 
14 
 | 
- Check the intake valves for valve deposits.
 
- If deposits are found, remove as necessary.
 
 
Were deposits found on the intake valves? 
 | -- 
 | 
Go to Step 16
 
 | 
Go to Step 15
 
 | 
15 
 | 
- Review all diagnostic procedures within this table.
 
- If all procedures have been completed and no malfunctions have
been found, review/inspect the following items:
 
| •  | Visual/physical inspection. |  
  
| •  | All electrical connections within a suspected circuit and/or system. |  
  
- If a problem is found, repair as necessary.
 
 
Was a problem found? 
 | -- 
 | 
Go to Step 16
 
 | Check for Service Bulletins 
 | 
16 
 | Operate vehicle within
the conditions under which the original symptom was noted. 
Does the system now operate properly? 
 | -- 
 | System OK 
 | 
Go to Step 2
 
 |