Misfire on cyl. 4

I have a random misfires on cyl. 4. I have moved plugs, wires, and ignition coil packs to see if the code would move but it still remains on cyl. 4. Start up is the worst, once it gets warm it seems to be fine.

My car has 80000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
You may have a clogged injector and carbon build up on the valves. Have the injectors cleaned out using a professional machine and cleaner. Then have the combustion chambers cleaned to try and dissolve some of the carbon build up on the intake valves. If it still misfires then have a compression test done to see if cylinder has problems with the piston or valves. If you need any help with this, consider YourMechanic, as one of our mobile technicians can diagnose your misfire and help you fix it accordingly.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

Cylinder 4 misfires can be caused by many reasons from a faulty ignition system, fuel system, or internal engine failure. The most common reason for this to happen is faulty or worn-out spark plug coil packs, especially if it`s been a while since you had a tune-up.
Common reasons for this to happen:

Faulty spark plugs or wires. Faulty ignition coil. Broken piston rings.

Causes of lean misfire that only affect one cylinder include a dirty fuel injector, an open or shorted fuel injector, or a problem in the fuel injector driver circuit (wiring or PCM). Compression problems that may cause a misfire include a burned exhaust valve, bent intake or exhaust valve, or leaky head gasket.
If an oxygen sensor or mass airflow sensor is failing, it could give incorrect data to your engine`s computer, causing the misfire.
If you do not fix whatever is causing the cylinder not to fire, it may cause serious and irreversible damage to your catalytic converter or engine, which are two of the most expensive parts to replace. Additionally, a car that is not firing on all cylinders may be inherently more dangerous to drive.
An engine misfire can be caused by bad spark plugs or imbalanced air/fuel mixture. Driving with a misfire isn`t safe and can damage your engine.
The most common causes of misfires are worn, improperly installed, and mishandled spark plugs, malfunctioning ignition coils, carbon tracking, faulty spark plug wires and vacuum leaks.
To find the cause of a misfire, start with checking for trouble codes in the onboard diagnostics system with a scan tool. The codes may not pinpoint a specific part, but they should identify the cylinder or cylinders that are misfiring as well as other systems that aren`t functioning properly.
Repairing or replacing a cylinder can range from $100 to $1,000. Different causes for misfires cause different severities of damage that each cost varying amounts to repair. These damages are: Slower fuel delivery issues can cost anywhere from $200 to $1,000.
Vacuum leaks, especially those that are confined to one cylinder, will cause the engine to idle unevenly and possibly misfire. This is because the vacuum leak allows additional air to reach the affected cylinder, diluting its air/fuel mixture.
your engine misfires and shakes: if a map sensor reports a false high pressure reading, the engine`s computer will signal for more fuel. this results in a rich mixture, which can foul the spark plugs and cause a cylinder not to fire. a misfiring engine will shake and transmit that motion into the cabin of the vehicle.
The OBD II system detects misfires on most vehicles by monitoring variations in the speed of the crankshaft through the crankshaft position sensor.
Common causes include ignition system troubles, fuel delivery issues, or leaking valves. However, a faulty or worn-out spark plug or ignition plug coil pack is the most common cause of the misfire. This is especially true if your car tune-up has been delayed for a while.
The type “A” misfire is the most serious condition and indicates impending catalyst damage. If detected, the Malfunction Indicator Lamp (MIL) may flash once per second to alert the driver that immediate service is required.
If left untreated, a cylinder misfire can lead to significant engine damage. Worse, if you experience a bad misfire while driving, it could result in an accident. This is why it`s important to treat engine misfires as soon as you detect them.
Any raw fuel in the catalytic converters quickly overheats them and leads to their destruction. If misfires occur severely then damage occurs quickly. If misfires are subtle, then damage may not occur for a year or two.
If left untreated, a cylinder misfire can lead to significant engine damage. Worse, if you experience a bad misfire while driving, it could result in an accident. This is why it`s important to treat engine misfires as soon as you detect them.
An engine misfire can be caused by bad spark plugs or imbalanced air/fuel mixture. Driving with a misfire isn`t safe and can damage your engine.
An engine misfire results from incomplete combustion (or zero combustion) inside one or more cylinders. But to you, the problem will usually feel like hesitation or shaking when the car is running. In modern vehicles, the Check Engine Light will also pop on when there`s a misfire.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Cylinder 4 misfire, fuel injector looks to be the problem, only misfires on start up or idle, is it safe to drive?
ANSWER : Driving for an extended period with a misfiring cylinder can certainly do damage. That cylinder will run hotter because of the misfire and piston and/or valve damage can occur. If you need help having this repaired, a certified professional from YourMechanic can inspect the misfiring situation and have this addressed properly.

Read Full Q/A … : Misfire on cyl. 4

Misfire on cyl. 4
ANSWER : You may have a clogged injector and carbon build up on the valves. Have the injectors cleaned out using a professional machine and cleaner. Then have the combustion chambers cleaned to try and dissolve some of the carbon build up on the intake valves. If it still misfires then have a compression test done to see if cylinder has problems with the piston or valves. If you need any help with this, consider YourMechanic, as one of our mobile technicians can diagnose your misfire and help you fix it accordingly.

Read Full Q/A … : Misfire on cyl. 4

One month ago cel came on I changed spark plugs to after market plugs. One month later cel on again with misfire code.
ANSWER : If the spark plugs hadn’t been changed until 130k, it was time for the to be replaced anyway. This is probably why the dealer went with that repair as worn spark plugs can cause misfires. Ignition coils are another part that may fail and cause misfires when they malfunction. A compression test and cylinder leak-down test will show if there is a problem with the valves. You can try having the coils replaced and the valves adjusted by the dealer. Consider hiring an experienced technician like one from YourMechanic who can come out and conduct the same tests as the dealer could and determine the cause for your check engine light.

Read Full Q/A … : Misfire on cyl. 4

I have a 2008 lincoln mkz. I ran the codes and am getting a o2 bank 4 sensor 4. I can’t even find anything online that says my car
ANSWER : Hi there. From what I am aware of, there isn’t a bank 4 sensor 4 on this vehicle or other Ford products. There are four total O2 sensors, (two upstream and two downstream), so the code you are getting might be related to one of the downstream sensors. If I were in your position, I would research the specific code you are getting (assuming it’s a Ford / Lincoln specific OBD code) or have a professional mobile mechanic complete a digital scan so they can download all stored error codes that should help you pinpoint the source of the issue you’re having.

Read Full Q/A … : Misfire on cyl. 4

Random Misfire on Nissan Sentra
ANSWER : There are at least two recalls of the 2003 Sentra involving engine management issues. Consequently, you should first check your VIN at the NHTSA website to see if your vehicle is affected by any recalls. Carefully check the EGR system. If EGR is stuck open you can get global misfiring. Check the integrity of the PCV system, too. The fuel system needs to be ruled out including the mundane, but real, possibility that you have a tankful of bad gasoline. The actual fuel system pressure should be tested and verified against factory specifications. Injector operation should be verified. PCM failures that can account for global misfiring are rare but they do happen. It will be helpful to look at the engine operation using a real time scanner and also download freeze frame data from the misfiring episodes. If you want these diagnostic steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a misfiring diagnostic and the responding certified mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Read Full Q/A … : Misfire on cyl. 4

Stuck in 4*4 low
ANSWER : The transfer case uses an encoder that is mounted on the transfer case that senses what range the transfer case is in. The encoder gives the transfer case module feedback when it switches the transfer case motor to to different ranges. The shift motor moves the shift fork inside the transfer case to give you the ranges from low to high or 2WD and 4WD.

You most likely broke the 3-4 clutch inside the transmission again from driving in low range. I would suggest pulling out the shift motor and trying to manually shift the transfer case to high range 2WD to see if the transfer case is operational and can shift internally to another range. This will help narrow down the problem to an internal or external shifting problem with the transfer case.

I would recommend having a certified mechanic, such as one from YourMechanic, come to your location and diagnose your transfer case shifting issue before you have the transmission repaired to prevent blowing it out again.

Read Full Q/A … : Misfire on cyl. 4

My car has been diagnosed with a misfiring cylinder 4. Will it be safe for me to drive it home 100 miles ?
ANSWER : From the description you have provided, it is advisable to have your vehicle’s #4 cylinder misfire fixed before taking the 100-mile trip home. Depending on the cause of the misfire, consequential damage could occur to the cylinder wall, piston, and/or catalytic converter.

If fuel continues to be delivered without the spark, the cylinder wall could be washed of oil (increasing piston and cylinder wall wear), and excess fuel could be present in the catalytic converter (substrate could melt down). If the cause of the misfire is valve train related, additional cylinder head damage could occur.

The misfire could be due to a faulty spark plug, a faulty ignition coil, or a faulty fuel injector.

There are other things, that could also cause the misfire. It is recommended that you get a certified technician, such as one from YourMechanic, to inspect your vehicle and determine the cause of the cylinder misfire.

Read Full Q/A … : Misfire on cyl. 4

hey Jay. I have a vw jetta 2011 4 cyl. my car has 60,000 miles was driving and felt a slight hesitation when accelerating uphill.
ANSWER : Diagnostic Trouble Code P0303 means that Cylinder No. 3 is misfiring but the causes of that misfiring can be very varied. The other Code that you probably saw, namely P0304, just refers to the same misfiring but it is occurring in a different cylinder, namely cylinder No. 4. Among the causes of cylinder misfiring are faulty spark plugs, low compression, damage or excessive wear of spark plug wires and/or coils, faulty fuel injector, clogged EGR valves or tubes, burned valves, improper ignition timing, vacuum leaks, leaking head gasket, faulty camshaft sensor, faulty crankshaft sensor, faulty mass air flow sensor, faulty oxygen sensor, faulty throttle position sensor, faulty catalytic converter, and others. If you want the cause pinpointed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a misfiring diagnostic and the responding certified mechanic will get this diagnosed and resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic.

Read Full Q/A … : Misfire on cyl. 4