FUEL INJECTION SYSTEM TROUBLESHOOTING
SERVICE MANUAL NUMBER 23
Page 5D-20
90-861326--1 MARCH 1999
Hesitation, Sag, Stumble Symptom (Continued)
8
1. Remove spark plugs and check for
wet plugs, cracks. wear, improper
gap, burned electrodes or heavy
deposits.
•
Refer to Distributor Ignition System.
NOTE: If park plugs are gas or oil fouled,
the cause of the fouling must be deter-
mined before replacing the spark plugs.
2. If a problem is found, repair as nec-
essary
Was a problem found?
-
Go to OBD
System
Check
Go to Step 9
9
1. Check for the ECT sensor shifted in
value.
2. Check for intermittent opens or short
to grounds in the ECT sensor, MAP
sensor and TP sensor circuits. Also
check or throttle linkage sticking,
binding or worn.
3. An intermittent failure may not store
a DTC.
4. If a problem is found, repair as nec-
essary.
Was a problem found?
-
Go to OBD
System
Check
Go to Step 10
10
1. Check for engine going into rpm
reduction mode.
2. If a problem is found, repair as nec-
essary.
Was a problem found?
-
Not
Applicable
to MerCruis-
er
EFI or MPI
Go to Step 11
11
1. Check for proper alternator voltage
output.
2. The voltage should be between spe-
cified values.
3. If a problem is found, repair as nec-
essary.
Was a problem found?
11-16
Volts
Go to OBD
System
Check
Go to Step 12
12
1. Check for faulty or incorrect thermo-
stat.
2. If a problem is found, repair as nec-
essary.
Was a problem found?
-
Go to OBD
System
Check
Go to Step 13
13
1. Check intake valves for valve
deposits.
2. If deposits are found, remove as
necessary.
Were deposits found on the intake
valves?
-
Go to OBD
System
Check
Go to Step 14
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