99 Yukon, runs great,but misfires when at low throttle settings at hiway speeds. no codes, recent major tune up. 170,000 miles.
Jan 14, 2011 at 2:07 PM
99 yukon 5.7l
1999 GMC YUKON
GORDON777
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Repair Safety Notice:
This information is for general instructional purposes only. Vehicle repair can be dangerous.
Verify all information, follow manufacturer service procedures, use proper tools and safety equipment,
and consult a qualified repair shop when needed.
Engine running rough or misfiring can be cause by the following:
https://www.2carpros.com/articles/engine-misfires-or-runs-rough
1.Defective spark plugs
2.Inadequate spark/coil,defective spark plug wire.
3.Lack of compression
4.False air leakage.
5.Faulty fuel injectors.
6.Insufficient fuel pressure.
7.Contaminated fuel.
8.EGR valve that is leaking.
9.Oxygen sensors.
10.Throttle position sensor.
11.Manifold absolute pressure sensor
12.Mass Airflow Sensor
13.Idle air control valve
Note: If it doesn't apply disregard it-
https://www.2carpros.com/articles/engine-misfires-or-runs-rough
1.Defective spark plugs
2.Inadequate spark/coil,defective spark plug wire.
3.Lack of compression
4.False air leakage.
5.Faulty fuel injectors.
6.Insufficient fuel pressure.
7.Contaminated fuel.
8.EGR valve that is leaking.
9.Oxygen sensors.
10.Throttle position sensor.
11.Manifold absolute pressure sensor
12.Mass Airflow Sensor
13.Idle air control valve
Note: If it doesn't apply disregard it-
Mar 19, 2011 at 12:17 AM