When the check engine light is on, have the engine trouble codes pulled and post them below in the comments. Just about any local auto parts store will do this for free. There is a good chance that an engine sensor is failing. Therefore it is difficult to pinpoint without the codes. When the check engine light is not on then the most likely cause is either bad gas or an engine misfire. A rough idle can be due to a large vacuum leak while the vehicle operates just fine at other times.
The misfire diagnostic may indicate a fault due to a temporary fault not necessarily caused by a vehicle emission system malfunction. Possible malfunctions include the following conditions:
I have cylinder 5 misfire code p0305 on my 2009 Pontiac G8 base 3.6L V6. I’ve tried messing with it. I switched the spark plugs and tested the coil pack on cylinder 5, the test showed it was fine. I had a “professional” shop look at it and they told me it seems like the head was cracked and the piston in cylinder 5 was burned. Which is impossible because my car does not over heat at all and turns on just fine. It runs pretty decent besides the misfire no leaks or anything! What could it be?
The P0305 code means that cylinder 5 is misfiring and or is randomly misfiring. Start by checking for intake leaks an if no leaks are found the next step is to replace the spark plugs on cylinder 5. Most common cause would be a faulty coil. Try swapping it with a different cylinder, clear the codes and see if the issue follows the coil. Don’t rule this out just because it passed your test. See if it passes mine. If the problem persist more tests needs to be done to diagnose problem, see “Possible Causes”
Pontiac Code P0305 – Cylinder 5 Misfire Detected
– Faulty spark plug 5
– Clogged or faulty fuel injector 5
– Faulty ignition coil 5
– Fuel injector 5 harness is open or shorted
– Fuel injector 5 circuit poor electrical connection
– Ignition coil 5 harness is open or shorted
– Ignition coil 5 circuit poor electrical connection
– Insufficient cylinder 5 compression
– Incorrect fuel pressure
– Intake air leak
Code P0305 Description
First of all, when a misfire occurs, engine speed will fluctuate. In addition, if the engine speed fluctuates enough to cause the Crankshaft Position (CKP) sensor signal to vary, the Engine Control Module (ECM) can determine that a misfire is occurring.
My catalytic convertor has been cut off of my 2006 Pontiac Grand Prix. And the check engine light was on when bought. I changed plugs and wires. When I accelerate the check engine light flashing off and on. When I slow down the flashing stops.
You will need to have the Engine Trouble Codes pulled. This is the only way to know why the check engine light is coming on and or flashing. Guessing is not a good idea when just about any local auto parts store will pull the codes for free. Post the codes below in the comments for more information.
If The Check Engine Light Flashing
The following may prevent more serious damage to your vehicle:
Reducing vehicle speed
Avoiding hard accelerations
Avoiding steep uphill grades
When you are towing a trailer, reduce the amount of cargo being hauled as soon as it is possible
If the engine light flashing stops and remains on steady, see “Check Engine Light Is On Steady” following.
If the light continues to flash, when it is safe to do so, stop the vehicle. Find a safe place to park your vehicle. Turn the key off, wait at least 10 seconds and restart the engine. If the light remains on steady, see “Check Engine Light Is On Steady” following. If the light is still flashing, follow the previous steps, and see your dealer for service as soon as possible.
Check Engine Light Is On Steady
You may be able to correct the emission system malfunction by considering the following:
Did you recently put fuel into your vehicle?
If so, reinstall the fuel cap, making sure to fully install the cap. The diagnostic system can determine if the fuel cap has been left off or improperly installed. A loose or missing fuel cap will allow fuel to evaporate into the atmosphere. A few driving trips with the cap properly installed should turn the light off.
Did you just drive through a deep puddle of water?
If so, your electrical system may be wet. The condition will usually be corrected when the electrical system dries out. A few driving trips should turn the light off.
Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel. Poor fuel quality will cause your engine not to run as efficiently as designed. You may notice this as stalling after start-up, stalling when you put the vehicle into gear, misfiring, hesitation on acceleration, or stumbling on acceleration. (These conditions may go away once the engine is warmed up.) This will be detected by the system and cause the light to turn on.
If you experience one or more of these conditions, change the fuel brand you use. It will require at least one full tank of the proper fuel to turn the light off.
If none of the above steps have made the light turn off, your dealer can check the vehicle. Your dealer has the proper test equipment and diagnostic tools to fix any mechanical or electrical problems that may have developed.
The car leaks water inside very badly. I understand through reading some blogs that this is a common problem. My guess is that the sunroof leak channel drains are all plugged up. I was told that these drains drain to the fender wells. Can you tell me how to locate these drains in the fender wells so that I can attempt to push a cable up through them to unclog them? I have looked everywhere for these drains and can’t locate them. I really don’t want to have to tear the whole interior apart to get to the top side of them. Thanks!
I am going to suggest a different approach because it may save you some time. Start from the top. Retract the sunroof to gain access tot he drain holes. Using an air compressor and appropriate air nozzle, blow air through the drain holes. In Addition check the seals (weather stripping) around the sunroof itself. Furthermore you can listen for where the air escapes to help locate the other end of the drains.
If just the passenger floor is wet, it may be due to a leak in the heater core. Check your coolant level to see if it is getting low.
My 2000 Pontiac Grand Am will run well, no check engine lights, etc. It will suddenly just shut off. When you pull over and put it in park wait a few minutes will start back up. Maybe runs a mile maybe another day. It does not spit and sputter, no warning at all. I have replaced the ignition module, alternator, serpentine belt, plugs, and fuel filter, also battery and fuel pump relay. When it shuts off if you try to restart it too soon it sounds like no fuel, but when I turn the key on I hear the fuel pump come on. I’m losing my mind. I got no idea what else to check. This is my daughters car. It has left her stranded several times in the last 2 weeks. Any ideas?
When it will not start you will need to determine what it is not getting.
Fuel – Fuel pressure and Fuel Injector Pulse
We know the timing is good because it does run well when it starts so no need to check that. May be as simple as a loose connection. A quick test for spark would be to spray starting fluid in the air filter and if it starts off of that you know it has spark. Now you can concentrate on the fuel system. You may follow the No Start Diagnostic Chart or try the most common failure part, the fuel pressure regulator.
My 2001 Pontiac Grand Am 3.4L started dying while driving down the road head scan done through an EVAP code and a random misfire code replaced ignition module all three coil packs spark plugs and wires and problem persisted had mechanic friend put a fuel pressure test iron it and it was way off Granite 47 PSI idling supposed to be I think 52 and while driving when you press on the gas the fuel pressure would actually go down so I replace the fuel filter just got done now car will not start turn the key and you can hear the fuel pump kick in and you can hear the relay click over but car still will not start this is my work vehicle I need help
After you replace the fuel filter you need to cycle the ignition key ON and OFF 10 times. Each time holding the key in the ON position for 5 seconds and repeat. This will prime the fuel system since the new fuel filter is installed empty. It should run after that but the fuel pressure should be rechecked. If it still goes down like before, you may need to replace the fuel pressure regulator and or the fuel pump itself.
Fuel Pressure Regulator Replacement
Relieve the fuel system pressure.
Disconnect the fuel pressure regulator vacuum line.
Remove the fuel pressure regulator attaching screw.
Using a shop towel to catch any spilled fuel, lift and twist the fuel pressure regulator in order to remove the fuel pressure regulator from the fuel rail.
Remove the retainer and spacer bracket from the rail and discard.
Remove the fuel pressure regulator from the engine fuel return pipe.
Remove the fuel pressure regulator inlet O-ring and the fuel return pipe O-ring and discard.
Warning! Connect the fuel return line before tightening the regulator attaching screw in order to prevent the regulator from rotating. Rotation of the regulator could damage the retainer and spacer bracket and lead to a fuel leak at the regulator inlet.
• Do not use compressed air in order to test or clean a fuel pressure regulator as damage to the fuel pressure regulator may result.
• Clean the fuel pressure regulator filter screen with gasoline if necessary.
• Do not immerse the fuel pressure regulator in a solvent bath in order to prevent damage to the fuel pressure regulator.
•Inspect the filter screen for contamination. If contaminated, replace the fuel pressure regulator.
•Lubricate the new pressure regulator inlet O-ring with clean engine oil and install on the regulator inlet.
•Lubricate the new fuel return pipe O-ring with clean engine oil.
•Install the fuel return pipe O-ring.
•Connect the fuel return pipe to the regulator.
•Install the new retainer and spacer bracket into the slot on the fuel rail.
Caution! Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.
Install the pressure regulator to the fuel rail.
Tighten the fuel return pipe fitting to 17 N·m (13 lb ft).
Connect the fuel pressure regulator vacuum line.
Install the pressure regulator attaching screw.
Tighten the pressure regulator attaching screw to 8.5 N·m (75 lb in).
Inspect and verify that the retainer and spacer bracket is engaged in the slots in the fuel rail. Grasp and pull on the regulator to ensure that the regulator is properly seated.
Connect the negative battery cable.
Inspect the fuel leaks using the following procedures:
Turn ON the ignition, with the engine OFF for 2 seconds.
hi I’m trying to see what would be causing this to happen. I start it up, it runs at correct idle till it warms up and then it wants to idle down to the point it wants to stall. I have my own theories but I need a second opinion. Thank you.
If there are no check engine light codes I would think cleaning the throttle body and putting in a new air filter would fix you right up. Clean the throat and edges of the butterfly in the throttle body. Use starting fluid and spray it on a rag and wipe. DO NOT spray into throttle body.
All of my doors, locks and drivers side mirror works on my Pontiac Bonneville EXCEPT my passenger side. The window, door lock and the mirror won’t work. We have checked the fuses and checked the wires with a voltage tester. What’s wrong?
Sounds like you have some more checking to do with the volt-meter. If everything works from the drivers side door switches but no the passenger side. The passenger side switch assembly is faulty or unplugged. If neither side switches work, then the wiring is faulty. In most cases the wiring harness becomes damaged at the door jam. This is common. Using a multi-meter you can check for voltage going to the passenger side switch and then leaving the switch to determine where the issue is.
2002 Pontiac Bonneville Power Window Wiring Diagram