Jeep Cherokee 2000 - Service Diagnosis-Mechanical

CONDITION POSSIBLE CAUSES CORRECTION
12. Faulty ignition coil 12. Test and replace, as necessary
(Refer to Group 8D, ignition system)
ENGINE STALLS OR ROUGH IDLE 1. Carbon build-up on throttle plate 1. Remove throttle body and
de-carbon. (Refer to Group 14 for
correct procedures)
2. Engine idle speed too low 2. Check Idle Air Control circuit.
(Refer to Group 14, Fuel System)
3. Worn or incorrectly gapped spark
plugs
3. Replace or clean and re-gap
spark plugs (Refer to group 8D,
Ignition System)
4. Worn or burned distributor rotor 4. Install new distributor rotor
5. Spark plug cables defective or
crossed
5. Check for correct firing order or
replace spark plug cables. (Refer to
Group 8D, Ignition System for
correct procedures.)
6. Faulty coil 6. Test and replace, if necessary
(Refer to group 8D, Ignition System)
7. Intake manifold vacuum leak 7. Inspect intake manifold gasket
and vacuum hoses. Replace if
necessary (Refer to Group 11,
Exhaust System & Intake Manifold)
8. EGR valve leaking or stuck open 8. Test and replace, if necessary
(Refer to group 25, Emission
Control Systems)
ENGINE MISSES ON
ACCELERATION
1. Worn or incorrectly gapped spark
plugs
1. Replace spark plugs or clean and
set gap. (Refer to group 8D, Ignition
System)
2. Spark plug cables defective or
crossed
2. Check Idle Air Control circuit.
(Refer to Group 14, Fuel System)
3. Dirt in fuel system 3. Clean fuel system
4. Burned, warped or pitted valves 4. Install new valves
5. Faulty coil 5. Test and replace as necessary
(refer to group 8D, Ignition System)
SERVICE DIAGNOSIS—MECHANICAL
ENGINE MECHANICAL DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
NOISY VALVES/LIFTERS 1. High or low oil level in crankcase 1. Check for correct oil level. Adjust
oil level by draining or adding as
needed
2. Thin or diluted oil 2. Change oil (Refer to Engine Oil
Service in this group)
3. Low oil pressure 3. Check engine oil level. If ok,
Perform oil pressure test. Refer to
this group for engine oil pressure
test/specifications
9 - 70 4.0L ENGINE XJ
DIAGNOSIS AND TESTING (Continued)