engine light-p303 cylinder 3 misfire, changed spark plugs,ingition coil and cylinder valves
Hi,
Ive had a problem with my car for a couple months now.I had the engine light come on, done a diagnostics test,i got back p303 cylinder 3 misfire.I changed the spark plugs,ignition coils and got the cylinder valves professionally changed.The car engine light still comes on whilst I am driving and then the car starts to go in lag mode where it starts to run lumpy.I turn the car off and on again and the car runs fine.However,there is a constant misfire the car is producing.There are times when the engine light comes on flashing.I turn the car off an the engine flashing light goes and then th
Experienced mechanics share their insights in answering this question :
Coils and plugs are usually the starting point for a misfire code, but some basic diagnostic work might save you some money. Sometimes I like to try swapping components from cylinder to cylinder to see if the misfire moves before buying expensive parts. There are a few other problems that could lead to a P0303, like ignition primary problems, vacuum leaks, or bad injectors, but those things are usually accompanied by other codes. It’s clear that you have a dead miss. When the ECU sees a consistent misfire, it shuts off the fuel to that cylinder to prevent damage to the catalyst. The the CEL will start blinking to warn you that you may be doing damage by continuing to drive. You’re at a point where you need to have a professional do some diagnostic work. by contacting Your Mechanic, you can have a technician come to your home or office to check out your misfiring VW and recommend a fix.
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
You might get a misfire code after spark plug replacement for an individual cylinder like a P0303. The code indicates a misfire in cylinder three. Sometimes the spark plug is dropped, and the ground electrode and the center electrode can make contact. Or the problem could be with the connection to the coil.
Several reasons could trigger a cylinder 3 misfire. 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.
Most new spark plugs are packed with plastic or paper sleeves to protect the air gap during shipping. When a sleeve protector is present, the air gap is usually correct. The potential for inadvertently creating a misfire is very real when installing new spark plugs.
A clogged or failed exhaust gas recirculation or crankcase ventilation valve or faulty oxygen sensor can send the wrong signals to the computer and cause misfires.
Yes. While the damage may seem small initially, the longer you drive with a bad oxygen sensor, the worse the damage will become. Eventually, you may experience rough idling, poor acceleration, engine misfires, an illuminated check engine light, and failed emission tests.
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.
What the P0303 code means. The P0303 DTC is set when the ECU detects multiple misfires from cylinder 3. Misfires cause the ECU to set the Check Engine Light and put the vehicle into a failsafe mode to prevent damage. The Check Engine Light will remain until the code is repaired.
For example, the issue can stem from a faulty spark plug or wire, which in the grand scheme of things is relatively easy to repair. However, the error code may also occur because of a faulty catalytic converter or defective computer system, which can vary in expense.
It is very unlikely that a bad O2 would cause a misfire. It is more likely that a misfire caused an O2 sensor code. A O2 sensor sends a info to the ECU telling it what is happening in the exhaust stream. The only thing the the O2 sensor does is reads the amount of oxygen in the exhaust.
A misfire on its own does not usually signal a serious mechanical problem. Very often, it is just a spark plug, ignition coil or a fuel injector that needs to be replaced. However, if you ignore the problem, more cylinders could start to malfunction, possibly to the point that the engine stops working entirely.
To answer your question in one word – YES, the wrong spark plugs or incorrect spark plug gap can and often will cause a vehicle`s engine to misfire or run incredibly inefficient.
Even a dirty MAF sensor can cause a lean code and/or misfire to occur. The engine may be stalling because it isn`t getting enough throttle opening.
Engine Misfires: A failing camshaft position sensor can cause your engine to misfire. Transmission Shifting Problems: The data sent to the engine control module can stop the transmission from shifting properly.
Misfiring Engine
This is caused when fuel fails to ignite consistently during the combustion cycle. It could be that the spark plugs are failing, but it could also mean that the charge from the battery isn`t strong enough, and the ignition coil needs replacing.
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.
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.
Engines that idle in a clunky or rough manner could be suffering from misfiring. In essence, when a misfire occurs and the air to fuel mixture in the cylinder becomes compromised, your engine essentially may jump up and down, causing your car to start and stop suddenly.
Once the engine is cranked, you should look for blue sparks along the spark plug gap. If you can see blue sparks, this proves your ignition coil is working correctly. If you don`t see blue sparks or you see orange sparks, this is a sign that there`s a problem with your ignition coil.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
engine light-p303 cylinder 3 misfire, changed spark plugs,ingition coil and cylinder valves
ANSWER : Coils and plugs are usually the starting point for a misfire code, but some basic diagnostic work might save you some money. Sometimes I like to try swapping components from cylinder to cylinder to see if the misfire moves before buying expensive parts. There are a few other problems that could lead to a P0303, like ignition primary problems, vacuum leaks, or bad injectors, but those things are usually accompanied by other codes. It’s clear that you have a dead miss. When the ECU sees a consistent misfire, it shuts off the fuel to that cylinder to prevent damage to the catalyst. The the CEL will start blinking to warn you that you may be doing damage by continuing to drive. You’re at a point where you need to have a professional do some diagnostic work. by contacting Your Mechanic, you can have a technician come to your home or office to check out your misfiring VW and recommend a fix.
MISFIRE CYLINDER NUMBER 3
ANSWER : Hi There,
There are several reasons that can cause a valve to burn. One is normal wear and tear. As miles are put on an engine, the constant pounding and heat erosion wears away the metal on the face of the valve and seat. The exhaust valve sheds most of its heat through the valve seat in the cylinder head, so when the face and seat become worn and the area of contact is reduced, the valve starts to run hot. Eventually the buildup of heat weakens the metal and pieces of it start to break or flake away. As this happens it can form hot spots that even speed up the process. As the valve begins to leak and compression drops, the result is a weak or dead cylinder and a noticeable drop in engine power and performance. A bad exhaust valve will also increase exhaust emissions by a considerable amount because it allows unburnt fuel to leak into the exhaust. Thus, high hydrocarbon (HC) emissions may also indicate a burned valve. Valve burning can also be caused by any condition that makes the engine run hot or elevates combustion temperatures. This includes cooling problems, abnormal combustion like detonation or pre-ignition, loss of exhaust gas recirculation (EGR), retarded ignition timing or lean fuel mixtures.
There are several reasons that can cause a valve to burn. One is normal wear and tear. As miles are put on an engine, the constant pounding and heat erosion wears away the metal on the face of the valve and seat. The exhaust valve sheds most of its heat through the valve seat in the cylinder head, so when the face and seat become worn and the area of contact is reduced, the valve starts to run hot. Eventually the buildup of heat weakens the metal and pieces of it start to break or flake away. As this happens it can form hot spots that even speed up the process. As the valve begins to leak and compression drops, the result is a weak or dead cylinder and a noticeable drop in engine power and performance. A bad exhaust valve will also increase exhaust emissions by a considerable amount because it allows unburnt fuel to leak into the exhaust. Thus, high hydrocarbon (HC) emissions may also indicate a burned valve. Valve burning can also be caused by any condition that makes the engine run hot or elevates combustion temperatures. This includes cooling problems, abnormal combustion like detonation or pre-ignition, loss of exhaust gas recirculation (EGR), retarded ignition timing or lean fuel mixtures.
Spark plugs,spark wires,icm,ecm,ignition coils,replaced engine,crankshaft sensor,harmonic balancer car still misfires, wont start
ANSWER : Hi there. If your car had overheating issues before this misfiring issue began, it is quite possible that you have some internal engine damage like a blown head gasket that is the primary source of your troubles. Other damage to cam sensors and ignition timing and fuel components can also cause these issues. Before you sink another dollar in attempting repairs, I would strongly recommend having a professional mobile mechanic from our team come to your location and complete a car is hard to start inspection so they can pinpoint the root source and recommend the best course of action.
I have an 4.7 HO engine for my jeep. Cylinder 5 misfire and low pressure on passenger side. Replaced spark plugs and coils.
ANSWER : Hi there. To be completely honest, anytime a head gasket service has been completed, I typically throw "common causes of an engine cylinder misfire" out the window. In most cases, a head gasket gasket fails due to an overheating problem. Although most mechanics will spend lots of time resurfacing cylinder heads, replacing valve guides or bent valves and push rods, what they tend to forget is that when an engine overheats, it typically destroys electrical harnesses and sensors. The first thing I would recommend is to check all ignition system electrical connections; especially to crankshaft and cam position sensors. A damaged or exposed electrical harness might short occasionally, which can cause the inconsistent misfiring problem. The low engine pressure on the passenger side might be a symptom of the cylinder five misfire issue, but could also be damage to a piston ring caused again by the head gasket failure.
new engine by ford hesitating, misfiring at wot. Changed spark plugs, crank pos. sensor, relearn ecm
ANSWER : Hi there. Trying to diagnose a misfiring issue is nearly impossible remotely. However, it’s not very easy at a location either. I would recommend reading this article on the common causes of an engine misfire and trying to trace issues down to the root source. In many cases when a complete engine swap is completed, an electrical harness or connection to a fuel injector is faulty or something simple like that is the cause. Besides the article, the only real advice we can offer is to have a professional mobile mechanic complete a car is misfiring inspection.
Car misfiring on cylinder three
ANSWER : Hello! We will be happy to assist. You have definitely been on the right path to finding the root of the misfire. However there are a few things left that I recommend checking. I suggest to check the spark at the spark plugs at each cylinder. There may be an issue with the coil pack causing the misfire. Also check the PCV valve because that is a known cause of a misfires on your particular vehicle. I suspect that the PCV valve and hose may be leaking and causing the misfire.
You may have the engine model which has the PCV valve located above the transmission next to the exhaust header. This engine model’s PCV valve is routinely looked over because most are unaware that there are two PCV valve systems and the first one is easily visible from the top. I also recommend checking the resistance and voltages at the coil packs with a multimeter. I have a friend whom worked as a technician at a Ford dealership once tell me of a problem with your generation of Focus in which the wiring to the coil packs were made too tight and the tension broke the wires overtime.
I would always recommend having a qualified mechanic, such as one from YourMechanic, assist you in diagnosing your engine misfire and assisting you in repairs.
Engine will not stay started. I have replaced idle control valve map sensor spark plugs spark plug wires no check engine light is
ANSWER : You have a problem with the distributor assembly. I recommend replacing the distributor assembly. This will replace all the possible sensors and coil for the ignition and fix the problem you have.
99 mercury sable 3.0 ohv is skipping. Change my spark plugs and wires plus the ing Coil. It is still misfiring in cylinder
ANSWER : You should check for fuel injector pulse at the injector with noid light connected to the injector connector. Retest system after clearing the codes to make sure the codes return for misfires on cylinders 3 and 4. The spark plug cables should be verified they are connected to the coil correctly or the #3 and #4 wires are crossed on the coil. If they were on wrong then clear codes and retest the system for clear codes and no misfires.
