Engine Performance problem
2003 Pontiac Montana 6 cyl Two Wheel Drive Automatic 104000 miles
The code said misfire #4 so we changed what we think is the #4 plug and plug wire and it didn't change anything. Can anyone confirm that the middle front spark plug is #4 cylinder? Or any other ideas. The van is misfiring.
Please tell me what your engine size is in liter and what is the code number
October, 3, 2009 AT 12:18 AM
The engine is a 3.4
Thank you so much for posting the pic, looks like we fixed the right plug and wire already.
October, 3, 2009 AT 12:22 AM
Sorry I don't have the code# any more.
October, 3, 2009 AT 8:16 AM
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.
October, 3, 2009 AT 8:20 AM
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.
October, 3, 2009 AT 1:29 PM
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 motor. We can't get to the rear plugs without pulling the motor.
October, 3, 2009 AT 9:27 PM
Well, to replace the coil it doesn't say you have to rotate the engine.....only on the plugs....here is the info.....
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
Courtesy of GENERAL MOTORS CORP.
Install the ignition coil. Install the 2 attaching screws. Tighten the screws to specification. See TORQUE SPECIFICATIONS. Connect the spark plug wires.
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.
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.
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:
" Spark plug fouling - Colder plug.
" 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.
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.
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.
October, 4, 2009 AT 1:44 AM
Thank you again for the info, we will get back at it tomorrow and let you know the outcome.
October, 4, 2009 AT 1:54 AM
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 don't have the strap to do this so that raises another problem.
Will be looking forward to hearing from you Amy
October, 4, 2009 AT 12:04 PM
All right well we just changed the ignition coil for 1 and 4 and nothing changed so he is now on his way back to o reilly to make sure the code was correct (maybe should've done this first. Lost now, we thought for sure that was the problem.