Spark plug number four

Tiny
AMY.1977
  • MEMBER
  • 2003 PONTIAC MONTANA
Six cylinder two wheel drive automatic 104,000 miles.

The code said misfire number four so we changed what we think is the number four plug and plug wire and it did not change anything. Can anyone confirm that the middle front spark plug is number four cylinder? Or any other ideas. The van is misfiring.
Thanks!
Friday, October 2nd, 2009 AT 7:03 PM

15 Replies

Tiny
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Hello,

Below is a picture for the firing order.

Please tell me what your engine size is in liter and what is the code number?


https://www.2carpros.com/forum/automotive_pictures/248015_1_180.jpg


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Friday, October 2nd, 2009 AT 9:05 PM
Tiny
AMY.1977
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The engine is a 3.4.
Thank you so much for posting the picture, looks like we fixed the right plug and wire already.
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Saturday, October 3rd, 2009 AT 12:18 AM
Tiny
AMY.1977
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Sorry, I do not have the codenumber any more.
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Saturday, October 3rd, 2009 AT 12:22 AM
Tiny
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Hello,

If you can get the code again that would be great. If it were me I would swap the ignition coil with the one next to it and see if the problem followed. If it did then I would change the coil.

Not sure if you know but Auto Zone or O'Reilly's can pull your codes for free.
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Saturday, October 3rd, 2009 AT 8:16 AM
Tiny
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Hello,

Also, it looks like you may have some recalls on your vehicle. The dealer may fix these for free. Please contact the dealer service department, give them the VIN number of your car and have them check on these to see if they apply to you.


https://www.2carpros.com/forum/automotive_pictures/248015_Montana_Recall_1.jpg


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Saturday, October 3rd, 2009 AT 8:20 AM
Tiny
AMY.1977
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Thank you so much for the advice. We were thinking maybe the coil. Do you know if you can get to it without pulling the engine. We cannot get to the rear plugs without pulling the engine.
Thanks again!
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Saturday, October 3rd, 2009 AT 1:29 PM
Tiny
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Hello,

Well, to replace the coil it does not say you have to rotate the engine. only on the plugs. here is the information:

IGNITION COILS

Removal

Turn ignition off. Disconnect the spark plug wires from the ignition coils. Note the position from which the wires are removed. Remove the 2 screws that secure the ignition coil to the ignition control module. Remove the ignition coil.

Fig. 31: Identifying Proper Spark Plug Routing At Ignition Coils


https://www.2carpros.com/forum/automotive_pictures/248015_31_3.jpg



Courtesy of GENERAL MOTORS CORP.

Installation

Install the ignition coil. Install the 2 attaching screws. Tighten the screws to specification. See TORQUE SPECIFICATIONS. Connect the spark plug wires.

SPARK PLUGS

Removal

CAUTION: Allow the engine to cool before removing the spark plugs. Attempting to remove spark plugs from a hot engine can cause the spark plugs to seize. This can damage the cylinder head threads. Clean the spark plug recess area before removing the spark plug. Failure to do so can result in engine damage due to dirt or foreign material entering the cylinder head, or in contamination of the cylinder head threads.

Contaminated threads may prevent proper seating of the new spark plug. Use only the spark plugs specified for use in the vehicle. Do not install spark plugs that are either hotter or colder than those specified for the vehicle. Installing spark plugs of another type can severely damage the engine.

1. Turn ignition off. To remove spark plugs from left cylinder bank (front cylinder head), remove the spark plug wires from spark plugs. Remove spark plugs from engine. To remove spark plugs from the right cylinder bank (rear cylinder head), remove the air cleaner intake duct. See AIR CLEANER INTAKE DUCT under AIR INDUCTION SYSTEMS.

2. Remove front wiper motor cover. See appropriate WIPER/WASHER SYSTEMS article in ACCESSORIES & EQUIPMENT. Set the park brake. Shift the transaxle into Neutral. Remove the engine mount strut bolts. See Fig. 32.


https://www.2carpros.com/forum/automotive_pictures/248015_32_2.jpg



3. Swing the engine mount struts aside. Install the Engine Tilter Strap (J-41131) to the engine. See Fig. 33. Pull on the engine in order to rotate the engine forward. Tighten the engine tilter strap. Remove the spark plug wires from the spark plugs. Remove the spark plugs from the engine.


https://www.2carpros.com/forum/automotive_pictures/248015_33_1.jpg



Inspection

1. Ensure that the correct spark plug is installed. An incorrect spark plug causes driveability conditions. Ensure that the spark plug has the correct heat range. An incorrect heat range causes the following conditions:
"Â Spark plug fouling - Colder plug.
"Â Pre-ignition, causing spark plug and/or engine damage - Hotter plug.

2. Inspect the terminal post for a bent or broken terminal post. See Fig. 34. Test for a loose terminal post by twisting and pulling the post. The terminal post should not move.


https://www.2carpros.com/forum/automotive_pictures/248015_34_2.jpg



3. Inspect the insulator for flashover or carbon tracking, soot. This is caused by the electrical charge traveling across the insulator between the terminal post and ground. Inspect spark plug boot for damage. Inspect the spark plug recess area of the cylinder head for moisture, such as oil, coolant, or water. A spark plug boot that is saturated causes arcing to ground.

4. Inspect the insulator for cracks. All or part of the electrical charge may arc through the crack instead of the electrodes. Inspect for evidence of improper arcing. Measure the gap between the center electrode and the side electrode terminals.

5. Inspect for the correct spark plug torque. Insufficient torque can prevent correct spark plug operation. An over-torqued spark plug causes the insulator to crack.

6. Inspect for signs of tracking that occurred near the insulator tip instead of the center electrode. Inspect for a broken or worn side electrode. Inspect for a broken, worn, or loose center electrode by shaking the spark plug. A rattling sound indicates internal damage. A loose center electrode reduces the spark intensity.

7. Inspect for bridged electrodes. Deposits on the electrodes reduce or eliminates the gap. Inspect for worn or missing platinum pads on the electrodes, if equipped. Inspect for excess fouling. Inspect the spark plug recess area of the cylinder head for debris. Dirty or damaged threads can cause the spark plug not to seat correctly during installation.

8. Brown to Grayish-Tan with small amounts of White powdery deposits are normal combustion by-products from fuels with additives. Carbon fouled - dry, fluffy, black carbon, or soot is caused by rich fuel mixtures such as leaking fuel injectors, excessive fuel pressure, restricted air filter element and incorrect combustion. Reduced ignition system voltage output which includes weak coils, worn ignition wires and incorrect spark plug gap can also cause carbon fouling.

9. Excessive idling or slow speeds under light loads can keep spark plug temperatures so low that normal combustion deposits may not burn off. Deposit fouling - oil, coolant, or additives that include substances such as silicone, very White coating, reduces the spark intensity. Most powdery deposits will not effect spark intensity unless they form into a glazing over the electrode.

Installation

CAUTION: Be sure plug threads smoothly into cylinder head and is fully seated. Use a thread chaser if necessary to clean threads in cylinder head. Cross-threading or failing to fully seat spark plug can cause overheating of plug, exhaust blow-by, or thread damage. Follow the recommended torque specifications carefully. Over or under-tightening can also cause severe damage to engine or spark plug.

1. Gap the spark plugs. See SPARK PLUGS under IGNITION SYSTEMS in SERVICE & ADJUSTMENT SPECIFICATIONS - 3.4L Montana, Silhouette & Venture. Install the spark plugs. Tighten the spark plugs to specification. See TORQUE SPECIFICATIONS.

2. Install the spark plug wires to the spark plugs. Return the engine to the proper position. Remove the engine tilter strap from the engine. Swing the engine mount struts in position. Install the engine mount strut bolts and tighten bolts to specification.

3. Install the air cleaner intake duct. See AIR CLEANER INTAKE DUCT under AIR INDUCTION SYSTEMS. Install front wiper motor cover. See appropriate WIPER/WASHER SYSTEMS article in ACCESSORIES & EQUIPMENT.

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Saturday, October 3rd, 2009 AT 9:27 PM
Tiny
AMY.1977
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Thank you again for the information. We will get back at it tomorrow and let you know the outcome.
Amy
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Sunday, October 4th, 2009 AT 1:44 AM
Tiny
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Hello,

I would try everything possible, lay on the fender well or across the engine etc to do this and then if you have to roll the engine. Many do not have the strap to do this so that raises another problem.

Will be looking forward to hearing from you Amy.

Good luck!
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Sunday, October 4th, 2009 AT 1:54 AM
Tiny
AMY.1977
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All right well we just changed the ignition coil for one and four and nothing changed so he is now on his way back to O'Reilly to make sure the code was correct (maybe should have done this first). Lost now, we thought for sure that was the problem.
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Sunday, October 4th, 2009 AT 12:04 PM
Tiny
AMY.1977
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Okay, got the code again, P0304 and now we are told to try fuel injector cleaner.
Do not know what to do if that does not work.
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Sunday, October 4th, 2009 AT 12:20 PM
Tiny
AMY.1977
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  • 9 POSTS
One other thing, we just found out is if we rev up the engine it will not go above 4000 rpm. It just bogs down and bounces between 3500 and 4000 rpm even if we have the gas pedal all the way down.
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Sunday, October 4th, 2009 AT 12:32 PM
Tiny
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Hello,

Well, the bad news is I have looked all through the manual for your vehicle and there is no P0304 code. Sometimes the code scanners give generic and what it thinks, like Mercedes Benz you definitely have to cross reference from a general code scanner.

Sever misfire can cause a catalytic converter to fail which can give the symptoms you are stating.

As for fuel injector cleaner I would recommend BG44K.

Are you sure all plugs are firing? Did you remove the plug wire and put something in the end and of it and have someone try to start the car and have the metal object really close to a piece of metal on the engine and see if you are getting a good strong popping blue spark. Do not have your hands on any part of the metal! If there is no spark, then it is electrical.

That way we can be sure if you are getting good spark.

The catalytic converter you will have to go to a muffler shop and have them check to see if it is plugged. Is it glowing red at all?

You may also have to get a fuel pressure check.
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Sunday, October 4th, 2009 AT 1:36 PM
Tiny
AMY.1977
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Hi,
Thank you so much for all the time you have spent on this for us. To be honest I do not understand what you mean about he code not being in the manual as it is a code for Pontiac in general is not? Are you telling me that out problem could have nothing to do with the number four spark plug at all?
Thank you, Amy
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Sunday, October 4th, 2009 AT 2:37 PM
Tiny
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Hello Amy.

Sometimes the codes on the scanner that are at parts stores etc like AZone are general codes. So when the scanner reads the car it tries to place it to as close as what the computer for that car says it is. So for a misfire on your car one of the codes in the manual is P0300 or P1381 not the code you gave me. So when I am working with a customer I ask for the code and what that code reader says it is then try to compare it to what the manual says for that specific vehicle. Sometimes we are right on and sometimes like this no.

So then you have to do more troubleshooting, which is why I suggested to pull a plug wire off of the spark plug and insert something into the end of it and have someone try to start the car and have the metal object really close to a piece of metal on the engine and see if you are getting a good strong popping blue spark. Do not have your hands on any part of the metal! If there is no spark, then it is electrical. Did you have the chance to do this to see if the plug was firing?

Then we can actually see what the car is doing. As for the fuel pressure a lack of fuel pressure can also cause a misfire so we are basically trying to narrow it down between codes and what the car is doing without using the expensive test machines sometimes we win, sometimes no.

There are times we have to end up having the customer take it and pay the eighty dollars or so to have it troubleshot and if they can fix it they have still saved money.
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Sunday, October 4th, 2009 AT 4:34 PM

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