What are the causes of engine cylinder misfire?

[VanJeremiah]

Here are the causes of engine cylinder misfire: 1. Issues with spark plugs, such as clogging or damage. 2. Problems with cylinder wires. 3. Faulty ignition coils. 4. Issues with fuel injectors, such as clogging or low voltage causing loss of injector data in the DME. 5. Problems with the air-fuel mixture. 6. Issues with cylinder pressure. Here are the hazards of engine cylinder misfire: 1. The most severe is damage to the catalytic converter. 2. The second most severe is an increase of over 1.5 times in the emission of harmful substances in the exhaust. 3. The third and least severe misfire can cause the vehicle's exhaust emissions to fail to meet standards.

[DelMarcus]

As an enthusiast who frequently tinkers with engines, I've encountered quite a few instances of cylinder misfires. The most common issue is with the ignition system—spark plugs aging or excessive carbon buildup can lead to unstable ignition, or the ignition coil might just not be performing well. On the fuel system side, clogged fuel injectors or insufficient fuel pressure can prevent gasoline from spraying properly or evenly, also causing misfires. Poor cylinder pressure is another culprit, whether it's due to valves not sealing tightly, piston ring wear leading to air leaks, or insufficient compression ratio making the air-fuel mixture hard to ignite. Then there are those sensors—like a faulty crankshaft position sensor sending incorrect signals, leaving the ECU clueless about when to fire. Oh, and don’t overlook aging wiring or loose connections, which can also act up. If something feels off—like rough idling or the car jerking—it’s best to pull the trouble codes and check things out promptly to avoid damaging the catalytic converter too.

[OPreston]

My car had experienced engine misfire before, with very obvious symptoms - the car would shake when I stepped on the accelerator and felt underpowered. Later we found out it was because several holes in the fuel injectors were clogged, causing inaccurate fuel injection. It's also possible your spark plugs have been used too long and the gap has widened - they need replacement. Checking the ignition coils' working condition is crucial; if one cylinder's ignition coil fails, that cylinder won't work. Additionally, incorrect air-fuel mixture ratio can cause problems too. For example, if the MAF sensor signal drifts, the ECU will miscalculate fuel injection, easily leading to incomplete combustion or failure to ignite. Mechanical issues are more troublesome - burnt valves or leaking piston rings causing insufficient compression pressure can prevent cylinder ignition. I suggest reading the trouble codes early to identify exactly which cylinder isn't working properly.

[SanCaleb]

Let's talk about engine misfires. The most likely culprits are the ignition system, such as a spark plug in poor condition or simply not firing in a certain cylinder, or a faulty ignition coil which is also quite common. Don't overlook the fuel system—clogged or malfunctioning fuel injectors are a frequent cause of misfires. Issues with intake and exhaust can also be to blame, like severe carbon buildup on valves preventing them from sealing properly, broken valve springs, or camshaft wear affecting valve operation, all of which can disrupt air-fuel mixture intake and pressure buildup. Loose electrical connections or damaged wiring causing short circuits are hidden troublemakers too. During a misfire, exhaust fumes may noticeably smell foul, with a sulfur-like odor. For older vehicles, cleaning the throttle body and fuel injectors might just do the trick—sometimes the problem isn't as complicated as it seems.

[JordanDella]

I reckon engine misfires usually boil down to those common culprits. Ignition components are the most likely suspects – a faulty spark plug, high-voltage wire, or ignition coil can all cause ignition failure. On the fuel side, unstable fuel pressure, aging fuel pump, clogged injectors, or even a dirty fuel filter can affect fuel delivery. Then there's carbon buildup – a frequent issue with older cars. When carbon accumulates on piston tops and valve backs, compression ratios change and combustion suffers. Insufficient cylinder pressure is another major flaw. Faulty signals from critical sensors like oxygen sensors or camshaft position sensors can also confuse the ECU. Oh, and some cars with ECU tunes or modified blow-off valves might experience misfires due to unstable programming or air leaks.

[VanDaniel]

I've seen misfires a lot during car repairs, usually caused by insufficient ignition energy or fuel supply issues. But the underlying reasons are quite varied: aging ignition coils breaking down and lacking energy, spark plugs with excessive gaps or too much carbon buildup leading to weak sparks, fuel injectors sticking and failing to spray fuel... Intake and exhaust valves not sealing properly, causing air-fuel mixture leakage during compression and insufficient pressure for ignition. Poor electrical connections, especially loose or corroded plugs connected to spark plugs or fuel injectors, resulting in intermittent signals. A faulty knock sensor can make the ECU misoperate the ignition timing. There's also the issue of low cylinder compression, which requires checking valve seals and piston ring conditions. Finally, a reminder: coolant leaking into the combustion chamber can also cause misfires—sniff the exhaust pipe for a sweet smell.