The intake manifold gaskets can develop external engine oil or coolant leaks. The intake manifold will need to be removed and the gaskets replaced to correct this issue. In some cases the plastic intake manifold my be damaged requiring replacement.
Problems for specific Pontiac Bonneville years:
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Most reported 2004 Pontiac Bonneville problems
It is common for the fuel level sensor in the fuel tank read the fuel level incorrectly. The sensor must be replaced to correct the condition. Our technicians recommend having the complete fuel pump module replaced on high mileage vehicles.
The steering may develop a clunk type noise from the upper intermediate steering shaft. Our technicians tell us that you should check with you local GM dealer to find out what the latest repair is for this condition.
The transmission pressure control solenoid may fail causing erratic shifting. Our technicians tell us that partial dis-assembly of the transmission is necessary to replace a failed pressure control solenoid.
The high pressure power steering hose will commonly leak fluid; it should be replaced.
The front struts may show signs of wear, or be excessively bouncy ride at freeway speeds. This may begin to occur at around 75,000 miles.
Illumination of the Check Engine Light can be caused by a loose or worn gas cap.
One or more heater & AC (HVAC) air delivery and/or temperature mode door actuator may fail. This can result in incorrect air delivery or temperature. If this occurs, fault code(s) stored in the HVAC control module should be available to assist with diagnoses.
An intake manifold vacuum leak can develop from a variety of sources, often causing illumination of the Check Engine Light with codes P0171 & P0174 stored. Thorough diagnoses will be necessary to pinpoint the cause in order to make the correct repairs. A "smoke" machine is often used to isolate the cause of difficult to find vacuum leaks.