1999 GMC 3500 Pickup Problems
RepairPal has identified the most common problems with the 1999 GMC 3500 Pickup as reported by actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.Refine by vehicle
Illumination of the Check Engine Light can be caused by a loose or worn gas cap.
The engine may develop a misfire due to worn valve seats. This fault will cause the Check Engine Light to illuminate. Our technicians tell us the misfire may or may not be felt while driving. They further recommend that both cylinder heads be removed and thoroughly inspected and repaired as necessary.
One or more fuel injectors may become stuck closed causing an engine misfire and the Check Engine Light to illuminate. Our technicians tell us that this problem can be caused by some fuel additives. There are special procedures which may be able to restore the affected injector. If this fails the affected injector must be replaced.
The spark plugs should be replaced every 100,000 miles. Our technicians recommend replacing the spark plug wires also at this time.
Vehicles equipped whit a 4 speed automatic transmission may develop a harsh 1-2 shift and/or illumination of the Check Engine Light with code P1870 stored. This can be caused by wear of the bore for the TCC isolator and regulator valves in the valve body. This condition does not commonly occur until the transmission reaches normal operating temperature. If the valve body is worn, replacement will be necessary to correct this concern.
The alternator may fail causing the battery to go dead, or an abnormal noise may develop. The dash warning light may or may not illuminate. A failed alternator will require replacement.
Our technicians highly recommend that the transmission is serviced every 30,000 miles to avoid problems and maintain optimal operating order.
One or more heater & AC (HVAC) temperature and/or air delivery mode door actuator may fail, resulting in improper temperature or air delivery. If this occurs, fault code(s) should be stored in the HVAC control module which should assist in diagnoses.
The quick-connect fittings for the heater hoses tend to leak engine coolant. This problem commonly occurs because the metal housing has become brittle, which can break and cause leaks.
The air conditioning compressor may develop an abnormal noise and require replacement. We recommend that whenever an AC compressor is being replaced for a noise condition, a filter kit should be installed to prevent any metal particles in the system from damaging the new compressor.
An engine vacuum leak may develop from the throttle body gasket causing a higher than normal idle speed. Failed gaskets should be replaced.
A coolant leak may develop from the water pump. This can result in an engine overheating condition. A leaking water pump will require replacement.